What does Psalm 54:6 mean?

David looked forward to worshiping in the sanctuary, despite being pursued by enemies (1 Samuel 23:19–20) and praying for God's rescue (Psalm 54:1–3). His confidence in God was so strong that he entrusted all justice and retribution into the Lord's care (Psalm 54:4–5). This verse continues that assured praise; David plans for how he will praise and honor God once the danger has been overcome. Because David had been rescued in the past (Psalm 54:7), he is all the more sure the Lord will preserve him in this situation.

As the name suggests, a "freewill offering" was not required. It was voluntary and would express David's gratitude for the Lord's goodness. Believers in the Church Age should voluntarily present themselves to the Lord out of gratitude for His kindnesses. Paul writes in Romans 12:1: "I appeal to you therefore, brothers, by the mercies of God, to present your bodies as a living sacrifice, holy and acceptable to God, which is your spiritual worship." In addition, Christian believers should thank the Lord always for present blessings and a glorious future. First Thessalonians 5:16–18 exhorts believers to "Rejoice always, pray without ceasing, give thanks in all circumstances; for this is the will of God in Christ Jesus for you." Hebrews 12:28–29 says, "Therefore let us be grateful for receiving a kingdom that cannot be shaken, and thus let us offer to God acceptable worship, with reverence and awe, for our God is a consuming fire."