The Lord did not need our service. He commanded us to follow him, but his was the gift of salvation. To follow the Saviour is to share in salvation; to follow the light is to enjoy the light. Those who are in the light do not illuminate the light but are themselves illuminated and enlightened by the light. They add nothing to the light; rather, they are beneficiaries, for they are enlightened by the light.
This is the glory of man: to persevere and remain in the service of God. For this reason the Lord told his disciples: You did not choose me but I chose you. He meant that his disciples did not glorify him by following him, but in following the Son of God they were glorified by him. As he said: I wish that where I am they also may be, that they may see my glory.