Jesus going into the desert for forty days had two meanings.
First, in miniature he was repeating Jewish history in his own life. That was in accord with something Paul wrote in his letter to the Ephesians. There, he wrote that God had a master plan by which he summed up all of history in the life of Jesus. Our Lord’s going into the water recalled the Israelites passing through the Red Sea. His spending forty days in the desert echoed the Israelites’ spending forty years in the desert.
The second meaning in his going into the desert to be tempted was that it was the beginning of his life’s work. That’s how he began his mission of saving us. We all know that he saved us by dying for us, and we think of his death as his death on the cross. But St. Paul teaches us that was not exactly the death by which he saved us. In itself, his painful death on the cross had no value. After all, there were two thieves suffering the same death on their crosses, and there was no value in their deaths.
In Chapter Six of his "Letter to the Romans" Paul said a key thing about the death by which Jesus saved us. In verse ten of that chapter Paul wrote, "His death was a death to sin." Paul, by saying Jesus died to sin meant that Jesus, by withstanding all temptations to sin, proved himself to be so impervious to temptation, he was “dead to sin.”
Today’s Gospel of the forty days of temptation by the devil was the opening campaign by which Jesus showed his strength against sin. It was followed by years of skirmishes during which he pushed aside temptations to anger, lust, and pride. The Letter to the Hebrews says he was tempted in every way that we are. Finally, in the Garden of Olives his duel with the devil had his sweat dropping like blood. And when he said, “Father, not my will, but thine be done,” he was dead t sin. He had saved us by that death.