Luke 4.1-2: And Jesus, full of the Holy Spirit, returned from the Jordan and was led by the Spirit in the wilderness (2) for forty days, being tempted by the devil. And he ate nothing during those days. And when they were ended, he was hungry. (ESV)
Chapter three of the Gospel of Luke gives the account of the beginning of the ministry of John the Baptist as the person who will get the hearts of the people ready for the appearance and ministry of Jesus. Jesus came to John and was baptized by him, and after this baptism God spoke in Luke 3.22 from heaven regarding Jesus, “You are my beloved Son; with you I am well pleased.” (ESV). But before Jesus began his public ministry, the devil was allowed the opportunity to tempt Jesus.
The Holy Spirit led Jesus into the wilderness for 40 days and Jesus did not eat during this time. Jesus was physically weakened from the hunger and he was isolated. Jesus was fully God, and fully human, and here he was tested to the utmost. The 40 days of not eating mean that this temptation by the devil will take place when Jesus is at his weakest, from the human perspective. The devil is going to do and say everything he can to persuade Jesus not to go forward with his ministry and complete God’s plan of redemption.