“Inwardly and outwardly”
Rend your heart.
Read Joel 2:12-17
You can give your friend or your parents a most beautiful present, but you can be sure that they will consider what your motives were for doing so. Why did you give those gifts? Was it with all your heart or only an outward show? If it was for show, then your love for them is superficial. Sooner or later this will come to light.
Through His servant Joel, the Lord called His people to rend their hearts. They were called to turn to Him with all their heart, not merely by giving some sacrifices. Turning to the Lord with all your heart is inward, real, and radical, not just an outward show. It also involves submission. In this turning, our heart lies open to the Lord, just as a boy reveals his heart to his girl friend and vice versa. The hearts of such young people are immersed with good thoughts towards one another. And that is what the Lord seeks from the hearts of His people.
The Lord chooses His own and elects them. But He also shows that He wants to be asked for His blessings. In verse 13, the Lord shows the ground of our relationship to Him: we may pray to Him, pleading upon His attributes. The Lord is gracious and merciful so we can pray for true sorrow for, and hatred of whatever would offend Him. The Lord will hear such prayers.
What is repentance?