Origen — On First Principles 3.1.18

Toward the saying “it is not of the one who wills or runs, but of God who shows mercy,” Solomon’s ascent-psalm helps: “Unless the Lord builds the house, those who build it labor in vain; unless the Lord guards the city, the watchman stays awake in vain.”

This does not stop us from building or watching. It shows that what is built without God, and what lacks his guard, is built in vain and kept without result. If we say this building is God’s work, not the builder’s, we are not wrong — something has happened on the human side, yet the successful deed is thankfully referred to God who brings it to completion. Human willing is not enough for the end, nor is the athletes’ running enough to take the prize.