John Calvin Commentary Psalms 147:10

"He delighteth not in the strength of the horse: He taketh no pleasure in the legs of a man." — Psalms 147:10 (ASV)

Not in the strength of the horse. After the Psalmist has shown that there is proof of divine goodness in every part of the world, he takes particular notice that people have no strength except what is given to them from above. He adds this with the express purpose of checking the pride by which almost all people are inflamed, and which leads them to trust in their own strength.

The meaning of the passage is this: if a person comes relying on their own strength, and with all the assistances that seem to them most powerful, this will only result in smoke and vanity. Indeed, by arrogating even the smallest thing to themselves, this will only be a hindrance to the mercy of God, by which alone we stand. The strength of the horse is mentioned by synecdoche to denote any kind of protection.

It is not that God is displeased with those things He has given us as helps (considered in themselves), but it is necessary that we be drawn away from a false confidence in them. For very often, when any resource is available, we are foolishly intoxicated and lifted up with pride.

Therefore, he contrasts the fear of God with the strength of both people and horses, and places his hope in God's mercy, suggesting that it is essential for us to show moderation in worshipping God with reverence and holiness, and in depending upon His grace. Thus we learn that God only condemns that strength which would take from Him the honor due to Him.