There is no bargaining with the devil. He only loves himself.
Jesus fasted for forty days and forty nights, after which he was hungry,
"Remember you are dust, and to dust you shall return."
When Catholics enter a Catholic church , and before they sit in a pew, they genuflect down on one knee. This is done for 3 reasons.
The devils intentions are to destroy God's plans. The devil is everywhere he thinks he can trick a soul and drive it to hell.
There are certain things that just work together like, peanut butter and jelly, pencil and an eraser, husband and wife, so too does fasting and prayer. One without the other is just not the same and not effective.
The Apostles knew their Jewish prayers and scripture, yet they were fascinated when they saw Jesus pray. They saw something very attractive, but they were not quite sure what.