Throughout the Old Testament, rending one’s garments was a sign of mourning or lamentation. It was an expression of extreme anguish over trouble that came upon someone quickly and unexpectedly.
The Lord used this type of language through the prophet Joel. He called the people to “return to [Him] with all [their] heart, and with fasting, weeping and mourning” (Joel 2:12). Because of their sin, calamity was coming upon them, yet God was offering them a chance to escape it.
God then said, “Rend your heart and not your garments” (Joel 2:13). In other words, an outward display of mourning was insufficient. They needed to be sorrowful from their heart over the sins they had committed against the Lord.
The prophet also encouraged them to “return to the Lord” and reminded them that God was “gracious and compassionate, slow to anger, abounding in lovingkindness” (Joel 2:13). They could be forgiven if they were truly sorrowful for what they had done. Likewise, when we sin, we need godly sorrow that leads to repentance (2 Corinthians 7:10). And God desires “all to come to repentance” because He is “not wishing for any to perish” (2 Peter 3:9).
So rend your heart and not your garments. Outward displays of remorse cannot replace repentance from the heart. God sees our hearts and wants us to wholeheartedly turn to Him.