John Calvin Commentary Psalms 105:26

"He sent Moses his servant, [And] Aaron whom he had chosen." — Psalms 105:26 (ASV)

He sent Moses his servant. Here the prophet briefly refers to those aspects of the people's deliverance that were worthy of particular notice. Had the Egyptians, of their own accord, allowed the people to depart, neither the service of Moses nor miracles would have been required. God then appointed that their deliverance should take place in such a way as to make it impossible to deny that he was its author.

Moses is called the servant of the Lord, to teach us that he was not self-appointed to his office, and that he attempted nothing by his own authority, but, as the minister of God, executed the office with which he had been entrusted. The same thing is expressed still more plainly with respect to Aaron, when he is said to have been chosen. What is attributed to each of these eminent men in particular applies equally to both; therefore, the statement should be understood as follows: God sent Moses and Aaron, his servants, not because of their own inherent suitability, or because they voluntarily offered him their service, but because he chose them.

This passage teaches us that those who are engaged in active and useful service for the Church are not prepared exclusively by their own exertions, or equipped for it by their own talents, but are stirred up to it by God. Moses was a man of heroic virtue; but, considered merely in himself, he was nothing.

Accordingly, the prophet would have all that is considered worthy of remembrance in Moses, as well as in Aaron, be ascribed to God alone. Thus it appears that whatever men do for the welfare of the Church, they owe the power to do it to God, who, out of his free goodness, has been pleased to honor them in this way.