Joel
Joel 2:13BSB·traditional attribution

So rend your hearts and not your garments, and return to the LORD your God. For He is gracious and compassionate, slow to anger, abounding in loving devotion. And He relents from sending disaster.

John Calvin Reformed @genevareformer

He then subjoins, Rend your heart, and not your garments, and turn to Jehovah your God. The Prophet again repeats that we ought to deal sincerely with God; for all those ceremonies, by which men imagine that they discharge their duties, are mere mockeries, when they are not preceded by a pure and sincere heart.

Matthew Henry Presbyterian @wholebiblehenry

We have here an earnest exhortation to repentance, inferred from that desolating judgment described and threatened in the foregoing verses: Therefore now turn you to the Lord. 1. "Thus you must answer the end and intention of the judgment; for it was sent for this end, to convince you of your sins, to humble you for them, to reduce you to your right minds and...

Commenting on Joel 2:12-17

John Gill Reformed Baptist @doctorgill

And rend your heart, and not your garments,.... Which latter used to be done in times of distress, either private or public, and as a token of grief and sorrow, Gen 37:34; nor was it criminal or unlawful, the apostles themselves used it, Act 14:14; nor is it absolutely forbidden here, only comparatively, that they should rend their hearts rather than their garments; or not...