Albert Barnes Commentary Matthew 28:20

"teaching them to observe all things whatsoever I commanded you: and lo, I am with you always, even unto the end of the world." — Matthew 28:20 (ASV)

Lo, I am with you. That is, by my Spirit, my providence, my attending counsel and guidance. I will strengthen, assist, and guide you. This also proves that Christ is Divine. If a mere man, or a creature of the highest order, how could he promise to be with his disciples always—or at all? They would be scattered far and wide. His disciples would greatly increase. If he was with them always, he was God; for no finite creature could thus be present with many men scattered in different parts of the world.

Unto the end of the world. The word rendered world, here, sometimes means age or state; and by some it has been supposed to mean, I will be with you until the end of this age, or during the continuance of the Jewish state, to the destruction of Jerusalem. But as the presence of Christ was no less necessary after that than before, there seems to be no propriety in limiting the promise to his own age. It may, therefore, be considered as a gracious promise to aid, strengthen, guide, and defend all his disciples, but more especially his ministers, to the end of time.