By faith Abraham, when he was tested, offered up Isaac, and he who had received the promises was in the act of offering up his only son, of whom it was said, “Through Isaac shall your offspring be named.” He considered that God was able even to raise him from the dead, from which, figuratively speaking, he did receive him back.
Fasting is a spiritual discipline that is taught in the Bible. Jesus expected His followers to fast, and He said that God rewards fasting....
For as often as you eat this bread and drink the cup, you proclaim the Lord's death until he comes.
Trust in the Lord with all your heart, and do not lean on your own understanding.