Legalism
Legalism is defined as "adding extra rules so you will not break the ones already in place."
Example:
Scripture says: "Don’t fornicate" That’s all!
Legalism says: To make sure you are not tempted to fornicate use the following guidelines:
don’t watch TV, don’t go to movies, don’t read magazines or newspapers, don’t listen to secular music, don’t go dancing, don’t go swimming, don’t go anywhere alone, don’t wear short sleeve shirts or shorts, don’t wear make-up, rings, earrings, or necklaces, don’t wear anything that makes you look to attractive, if a lady has long hair wear it up so she will not tempt anyone, to be safe make yourself as unattractive as possible, etc.

Paul said:
1 Corinthians 4:6 ...learn from us the meaning of the saying, "Do not go beyond what is written." (NIV)
This means if it is not directly stated in scripture don’t say you have to do it or you can’t do it.

Jesus said:
Mark 7:5-18 So the Pharisees and the scribes asked him, "Why do your disciples not live according to the tradition of the elders, but eat with defiled hands?" ⁶ He said to them, "Isaiah prophesied rightly about you hypocrites, as it is written, ‘This people honors me with their lips, but their hearts are far from me; ⁷ in vain do they worship me, teaching human precepts as doctrines.’ ⁸ You abandon the commandment of God and hold to human tradition." ⁹ Then he said to them, "You have a fine way of rejecting the commandment of God in order to keep your tradition! ¹⁰ For Moses said, ‘Honor your father and your mother’; and, ‘Whoever speaks evil of father or mother must surely die.’ ¹¹ But you say that if anyone tells father or mother, ‘Whatever support you might have had from me is Coban’ (that is, an offering to God) -- ¹² then you no longer permit doing anything for a father or mother, (Matthew 15’s version ‘then that person need not honor the father.’) ¹³ thus making void the word of God through your tradition that you have handed on. And you do many things like this." (NRSV)

1 Peter 1:18 knowing that you were not redeemed with corruptible things, like silver or gold, from your aimless conduct received by tradition from your fathers, but with the precious blood of Christ (NKJV)
Legalism is one manifestation of the sin nature, called judging. See Mat. 7:1
Legalism can also be brought in by assuming that the mandates given to the Jews under the old covenant are in force on Christians under the new covenant.

Compare what Jesus and Paul said:
Luke 5:36-39 He told them this parable: "No one tears a patch from a new garment and sews it on an old one. If he does, he will have torn the new garment, and the patch from the new will not match the old. ³⁷ And no one pours new wine into old wineskins. If he does, the new wine will burst the skins, the wine will run out and the wineskins will be ruined. ³⁸ No, new wine must be poured into new wineskins. ³⁹ And no one after drinking old wine wants the new, for he says, `The old is better.’" (NIV)

Galatians 3:17 What I mean is this: The law, introduced 430 years later, does not set aside the covenant previously established by God and thus do away with the promise. (NIV)

The meaning here is clear. Jesus by making the new covenant fulfilled the promise he gave to Abraham of bringing salvation to all who believe. The "old," salvation by promise, is better than the Law which is the "new". No one who understands this would dare mix Law and Grace.

Galatians 3:19 Why then the law? It was added because of transgressions, until the offspring would come to whom the promise had been made; and it was ordained through angels by a mediator. (NRSV)

Paul has stated that the Law of Moses was given by the holy angels not by God himself. See also Acts 7:38 and Hebrews 2:2. This sets the stage for his teaching of Angel Worship and Will Worship.

Angel Worship
Colossians 2:8, 14-19 Beware lest anyone cheat you through philosophy and empty deceit, according to the tradition of men, according to the basic principles of the world, and not according to Christ.
¹⁴ (Jesus) having wiped out the handwriting of requirements that was against us, which was contrary to us. And He has taken it out of the way, having nailed it to the cross. ¹⁵ Having disarmed principalities and powers, He made a public spectacle of them, triumphing over them in it. ¹⁶ So let no one judge you in food or in drink, or regarding a festival or a new moon or sabbaths, ¹⁷ which are a shadow of things to come, but the substance is of Christ.
¹⁸ Let no one cheat you of your reward, taking delight in false humility and worship of angels, intruding into those things which he has not seen, vainly puffed up by his fleshly mind, ¹⁹ and not holding fast to the Head, from whom all the body, nourished and knit together by joints and ligaments, grows with the increase that is from God.

Paul is saying if you put anything above Christ it is idolatry. If the angels brought the law and Christ did away with it, but you kept practicing the law anyway, your putting it above Christ, or in other words worshipping the angels instead of him. See also: Gal. 2:19, Josephus Ant. 15.5.3, Deut. 33:2, Acts 7:53, Jub. c.1

Consider the parable of the butler:
If you went over to a friends house to see him and were told by the butler that to do so you must first call and make an appointment then come half an hour early, come to the side entrance, call for the butler who then made you take off your shoes and put on special ones (for the Persian rugs), wash your hands, recite scripture (to check your worthiness), tell him what this visit is about and then if he thinks its important enough to interrupt the Master you will get to see him. After a time the Master adopts you. And he says "as my son you come over anytime. Just come in the back door and don’t bother with anything the butler says. All that stuff is for business not family." Now at that point if you said "if I ignore the butler’s rules he may not let me see father" or "The butler may punish me" you would be honoring the servant rather than the Master.

Will Worship
Colossians 2:20-3:2 Therefore, if you died with Christ from the basic principles of the world, why, as though living in the world, do you subject yourselves to regulations-- ²¹ "Do not touch, do not taste, do not handle," ²² which all concern things which perish with the using—according to the commandments and doctrines of men? ²³ These things indeed have an appearance of wisdom in self-imposed religion (Will worship KJV), false humility, and neglect of the body, but are of no value against the indulgence of the flesh. (NKJ)

Those Will Worshipping would say "Through the power of my own will I alone will set up a way to avoid temptations and conquer sin." Paul says whether or not you use Moses law (angel worship) or some invention of your own (will worship) it only leads to death. The reason is because you are always focusing on sin.

The Solution
Colossians 3:1-2 Since, then, you have been raised with Christ, set your hearts on things above, where Christ is seated at the right hand of God. ² Set your minds on things above, not on earthly things. (NIV)

Philippians 4:8 Finally, brothers, whatever is true, whatever is noble, whatever is right, whatever is pure, whatever is lovely, whatever is admirable-- if anything is excellent or praiseworthy-- think about such things. (NIV)

Sin must be dealt with and talked about occasionally but not constantly. The only way out is to only think about righteousness and what good you can do. Setting your mind on heavenly things not on evil things. This is the only way to be free and truly holy.

If Paul were here today I believe he would extend his teaching of Angel worship and Will worship to include the following:
Grace Worship: These who believe grace is a power whereby they can become sinless.
Faith Worship: Those who believe by their faith they can command sinlessness, health, and wealth.
Water Worship: Those who believe baptism will save them.
Flesh Worship: Those who believe Circumcision will save them.

Liberalism
Liberalism is defined as "explaining things away so you do not have to do them."
Example:
Scripture says : "don’t fornicate" See 1 Corinthians 6:15-20
Liberalism says: True, but to make sure they are the right one and we don’t have any one parent families (which is what God really meant) live with the person first.
or
Scripture says : "homosexuality is an abomination" See Romans 1:24-32
Liberalism says: No. God really only meant that sexual violence is wrong. Its OK between two consenting adults.
or
Scripture says : "be Holy for I am Holy" 1 Peter 1:16
Liberalism says: It would be nice but in today’s society it's not possible, so why try. We will just wait and when we get to heaven we will be holy.

In other words Liberalism always says: God never knows what he is talking about, so we have to interpret it for the people to truly understand.
Liberalism seeks to do this because it is difficult to keep from sinning, and not find an excuse for it, when you know you are wrong. However, if you can convince yourself it is not really sin but righteousness then you can give yourself to it whole heartedly. Scripture calls this hardening your heart. See Hebrews 4:1-7

Jesus warned about liberalism in saying:
Matthew 18:6 But if anyone causes one of these little ones who believe in me to sin, it would be better for him to have a large millstone hung around his neck and to be drowned in the depths of the sea. (NIV)

Joshua 1:7 Only be strong and very courageous, being careful to act in accordance with all the law that my servant Moses commanded you; do not turn from it to the right hand or to the left, so that you may be successful wherever you go. (NRSV)
The Jews here are being instructed to obey God, not to go liberal, far left, or to go legalistic, far right, but to simply do what God commanded, no more or less.

Paul says the same:
1 Corinthians 4:6 learn from us the meaning of the saying, "Do not go beyond what is written." (NIV)
Don't add to or take away from the scriptures.

John said:
Revelation 22:18-19 I warn everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to that person the plagues described in this book; ¹⁹ if anyone takes away from the words of the book of this prophecy, God will take away that person's share in the tree of life and in the holy city, which are described in this book. (NRSV)

Turning to the right hand, or adding to is legalism. Turning to the left hand, or taking away from is liberalism. We are solemnly warned not to do either! If we presume to know best and force the scriptures to fit our theology, that in itself is the sin of presumption.

Psalm 19:13 Keep back thy servant also from presumptuous sins; let them not have dominion over me: then shall I be upright, and I shall be innocent from the great transgression. (KJV)
Romans 14:13 Therefore let us stop passing judgment on one another. Instead, make up your mind not to put any stumbling block or obstacle in your brother's way. (NIV)
1 Corinthians 8:9,12,13 Be careful, however, that the exercise of your freedom does not become a stumbling block to the weak. ¹² When you sin against your brothers in this way and wound their weak conscience, you sin against Christ. ¹³ Therefore, if what I eat causes my brother to fall into sin, I will never eat meat again, so that I will not cause him to fall. (NIV)
James 1:5-6 If any of you lacks wisdom, he should ask God, who gives generously to all without finding fault, and it will be given to him. 6 But when he asks, he must believe and not doubt. (NIV)

See also Ecc. 7:16-18 NIV