Jesus was Israel reduced to one. In the desert, many people of Israel fell in the trials described in the Exodus and until they entered the Promised land. The trials of the flesh
were difficult to overcome. Jesus’ time in the wilderness for forty days was a reminder of their trials. There, he faced the temptations of the evil one. He experienced the troublesof the flesh, but Jesus was both God and man. It was in His victory that God proclaimed that this was His Son in whom He was well pleased.
In Part II, the devil offers Jesus the world, but it is not really his to give. The devil offers humanity many thing, but his "promises" always fall short. God holds out a far better offer: eternal life in His Son.
The hymn: The King of Love My Shepherd Is (public domain).
The painting: Christ in the Desert by Ivan Kramskoy, 1872. (public domain).