Moses :
Deuteronomy 9:9-18
Moses fasted for 40 days when he went up to the mountain to receive the commandments of God written on stone tablets. This was an unusual and miraculous fast if we take it at face value. Moses says that he did not eat food nor drink water during the 40 days (Deuteronomy 9:9). Let’s assume that means he did not drink anything else either. A human body cannot survive extended periods of time without water unless God works some kind of miracle.
After he came down from the mountain of God and saw the people transgressing the commandments that were just given, Moses angrily breaks the tablets of stone. After a time he ascends the mountain once again and proceeds to fast another 40 days without food and water before receiving the law once more (Deuteronomy 9:18, 25, 26; 10:10).
Y'sha :
Matt 4:1
The most dramatic fast in Scripture is Jesus’ fast of forty days and forty nights. Matthew, Mark and Luke all report the event.
Matthew writes that Jesus “was led up by the Spirit into the wilderness to be tempted by the devil.” (Matt. 4:1)
After being baptized by John the Baptist, Jesus was tempted by the devil for 40 days and nights in the Judaean Desert. During this time, Satan came to Jesus and tried to tempt him. Jesus having refused each temptation, Satan then departed and Jesus returned to Galilee to begin his ministry. During this entire time of spiritual battle, Jesus was fasting.
The writer of the Epistle to the Hebrews also refers to Jesus having been tempted "in every way that we are, except without sin."[4]
Mark's account is very brief, merely noting the event. Matthew and Luke describe the temptations by recounting the details of the conversations between Jesus and Satan. Since the elements that are in Matthew and Luke but not in Mark are mostly pairs of quotations rather than detailed narration, many scholars believe these extra details originate in the theoretical Q Document.[5] The temptation of Christ is not explicitly mentioned in the Gospel of John but in this gospel Jesus does refer to the Devil, "the prince of this world", having no power over Him.[6]