Joel 2

The first part of this chpt. is God's judgement. Next is a call to return to God, but it's a turning of the hearts not actions. Verse 13 declares rend your heart not your garments. See we often want to immediately address the outward behavior, but God is asking for the heart. We use the expression, "let's get to the heart of the matter", which is always the bigger issue. If a child is disrespectful to a parent, we don't just want to correct the behavior, we want them to understand respect.
The next call is for everyone to be a part of this repentance. Not just some but women, men, children, elders, and priests are called out to fast, pray, come together in worship, and bring offerings. A cleaning of house so to speak. Then we have the Lord's promise. A promise of provisions, protection, rain, and to bless even to make up for what the locusts had taken. Then an even greater promise of spiritual blessing even to the end. There is another day of judgement coming, but the promise that anyone who calls on the name of the Lord will be saved.
Keep your heart turned toward Christ. The spirit is willing but the flesh is weak. So be encouraged. Live in the spirit and accept God's forgiveness and live for Him. Our behavior is simply a biproduct of our relationship to Him.