Here is what the early church fathers said about prayer:

• Irenaeus 178 AD
• Against Heresies 2.32 - Gnostics try to pass over to the state of perfection. Some Christians do certainly and truly drive out devils, so that those who have thus been cleansed from evil spirits frequently both believe in Christ, and join themselves to the Church. Others have foreknowledge of things to come: they see visions, and utter prophetic expressions. Others still, heal the sick by laying their hands upon them, and they are made whole. Yea, moreover, as I have said, the dead even have been raised up, and remained among us for many years. The Church does not perform anything by means of angelic invocations, or incantations, or by any other wicked curious art; but, directing her prayers to the Lord.
• Fragment 3 - John and Polycarp observed the fast of Yom Kippur. Most Christians observe the festival but not the fast. Some fast one day, others two days, and some try for 40. Some stand for prayer others kneel for the prayer of Yom Kippur.
   
• Hippolytus 170-236 AD
• The Refutation of all Heresies 9.16 pray from early dawn
  

More to Come!