John Calvin Commentary Psalms 32:9

"Be ye not as the horse, or as the mule, which have no understanding; Whose trappings must be bit and bridle to hold them in, [Else] they will not come near unto thee." — Psalms 32:9 (ASV)

Be not like the horse or mule. David now briefly explains the substance of the counsel which he formerly said he would give. He exhorts all to learn with quietness, to lay aside stubbornness, and to put on the spirit of meekness.

There is much wisdom, too, in the advice which he gives to the godly to correct their obstinacy; for if we were as attentive to God’s corrections as we ought, everyone would eagerly hasten to seek his favor.

Why is so much slowness found in all, if not because we are either stupid or rebellious? By likening the rebellious, therefore, to brute beasts, David puts them to shame, and at the same time declares that it will be of no use to them to “kick against the pricks.” Men, he says, know how to tame the fierceness of horses by bridles and bits; what then do they think God will do when he finds them intractable?