Then they remembered. And then eight days later, when going to the mountaintop to pray, only Peter, James and John went along, and even they went to sleep while He prayed. However they still had not learned. You see, prayer does not come naturally to the believer. One cannot pray successfully and effectually just because of a desire to do so.
Prayer is a skill to be learned and developed.
Jesus, praying all night, rising up early, etc. Prayer is not learned just by hearing good teaching concerning it, for Jesus taught His disciples as much on prayer as on any other subject of Christian living. Desire is not enough, example is not enough, and just lessons do not teach us. In Acts, we find the same men who found it difficult to pray three hours, praying for seven to ten days. But most of all, Lord, teach us TO pray.