Jesus is our endless source of life.
Jesus is our bond with the origin of life. Being God, He has life in himself. By becoming man, He transmits that life to all those who believe in him. Jesus, drawing closer to the reality of his disciples, makes them see that he himself is the vine and they are the branches. It is indispensable for the branches to remain attached to the vine if they want to have life and give fruits. The branch cannot bear fruit by itself if it's separated of the vine.
John 15:1.
Offspring.