"Then will the Lord be jealous for his land, and pity his people."

The book of Joel is a prophetic book in the Old Testament, and this verse marks a turning point in the book, where God's ultimate restoration and redemption are promised to the people of Judah. The Prophet Joel is speaking on behalf of God, calling for a national repentance and a return to the Lord. In the verse before this one, the people are urged to turn to the Lord with fasting, weeping, and mourning. And in the verse after, it is promised that the Lord will respond to their repentance.

The verse starts with "Then" indicating that the fulfillment of the earlier mentioned conditions, the fasting and repentance, will lead to the Lord's reaction. This reaction can be seen as an expression of God's mercy, love, and protection for His people. It also emphasizes the idea that God is a jealous God, not in the human sense of the word, but in the sense that He is protective and fervently loves His people.

The phrase "be jealous for his land" can be interpreted as God's protective nature for His people and His desire to see them walk in righteousness and be dedicated to Him. It emphasizes God's deep care and concern for the land that He had given to the Israelites, and His determination to see it populated with a righteous and faithful nation. The land is not only the physical territory but also the people who inhabit it, and God's jealousy for the land is an expression of His desire for His people to live in accordance with His will and purposes.

The verse also highlights God's compassion and pity for His people. The term "pity" signifies God's tenderness and kindness towards His people. Despite their unfaithfulness and disobedience, God's heart is moved with pity for His people, and He is willing to pour out His mercy and love upon them when they turn back to Him.

This verse is also about restoration and God's faithfulness. The promised reaction of the Lord, his jealousy and pity for his people, signifies that God will restore and heal his people and the land. He will not abandon them despite their waywardness, but will instead show them mercy and compassion. This can also be seen as a demonstration of God’s unchanging nature and His faithfulness to his covenant with the people of Judah.

In terms of context, this verse comes in the middle of Joel's call to repentance. The people had experienced a plague of locusts, which had devastated the land, and Joel saw this as a warning from God for the people to turn back to Him. The call to repentance is found throughout the book of Joel, and this verse marks the point in which God's response to their repentance is promised.

Symbolically, this verse can be seen as a picture of God's love for His people and His longing for them to be in a right relationship with Him. It also represents the idea of God as a protector and a compassionate father, who is willing to forgive and restore His people when they turn to Him in humility and repentance.

In conclusion, Joel 2:18 is a powerful and hope-filled verse that reflects God's love, mercy, and faithfulness. It highlights God’s protective nature and His deep desire to see His people restored and reconciled to Him. It also emphasizes the importance of repentance and returning to the Lord, as a means of experiencing His compassionate and redemptive response. Overall, it is a verse that speaks to the enduring love and faithfulness of God towards His people.