Psalms 136:17 (KJV) reads, "To him which smote great kings: for his mercy endureth for ever." This verse is part of a longer psalm that is often referred to as the "Great Hallel," which is a collection of psalms (Psalms 120-136) that were traditionally sung during the Passover feast.

The verse "To him which smote great kings: for his mercy endureth for ever" is a declaration of God's power and sovereignty over the rulers of the earth. It speaks to the idea that God is the ultimate authority and that his mercy is eternal. The verse serves as a reminder of God's ability to defeat even the most powerful earthly rulers and of his enduring love and compassion for his people.

One of the key themes of this verse is the sovereignty of God. Throughout the Bible, there are numerous examples of God's ability to overcome the plans and schemes of earthly kings and rulers. This verse serves as a reminder of God's ultimate authority and power, as well as his ability to bring about justice and deliverance for his people.

Another theme present in this verse is the mercy of God. The psalmist emphasizes that God's mercy endures forever, even in the face of great opposition and powerful enemies. This serves as a source of comfort and hope for those facing challenges and adversity, as it reassures them that God's love and compassion will never fail.

The context of this verse is also significant. The psalm as a whole serves as a reflection on the history of Israel and the many ways in which God has shown his faithfulness and mercy to his people. It recounts the story of the Israelites' deliverance from slavery in Egypt, their journey through the wilderness, and their eventual entry into the Promised Land. The verse "To him which smote great kings" can be seen as a reference to the victories that God granted to the Israelites as they entered the land of Canaan, conquering powerful nations and kings along the way.

In terms of symbolism, the "great kings" mentioned in the verse can be seen as representing not only literal earthly rulers but also any form of opposition or resistance that God's people may face. The verse serves as a reminder that God is able to overcome any obstacle or enemy, no matter how powerful or intimidating they may seem.

Overall, Psalms 136:17 (KJV) is a powerful declaration of the sovereignty and mercy of God. It serves as a source of encouragement and hope for believers, reminding them of God's ability to overcome any challenge and his unwavering love for his people. The verse also invites readers to reflect on their own experiences of God's faithfulness and to trust in his enduring mercy in the face of adversity.