Albert Barnes Commentary Matthew 4:2

"And when he had fasted forty days and forty nights, he afterward hungered." — Matthew 4:2 (ASV)

Had fasted. He abstained from food.

Forty days and forty nights. It has been questioned by some whether Christ abstained completely from food, or only from bread and the food to which He was accustomed. Luke says (Luke 4:2) that He ate nothing. This settles the question.

Mark says (Mark 1:13) that angels came and ministered to Him. At first, this might seem to imply that He ate during that time. However, Mark does not specify when the angels performed this service of kindness. We are therefore free to suppose that Mark meant to say it was done at the end of the forty days, especially since Matthew, after giving an account of the temptation, says the same thing (Mark 4:2).

There are other instances of individuals fasting forty days recorded in the Scriptures. For example, Moses fasted forty days (Exodus 34:28), and Elijah also fasted the same length of time (1 Kings 19:8). In these cases, they were undoubtedly miraculously supported.