This psalm praises God for his awesome power. It was most likely written to celebrate the defeat of Sennacherib's army after it invaded Judah (see 2Ki 18:13-19, 2Ki 18:37).
Psalms 76:10
How can defiance bring glory to God? Hostility to God and his people gives God the opportunity to do great deeds. For example, the pharaoh of Egypt refused to free the Hebrew slaves (Exo 5:1-2) and thus allowed God to work mighty miracles for his people (Exo 11:9). God turns the tables on evildoers and brings glory to himself from the foolishness of those who deny him or revolt against him. God's wrath expressed in judgment brings praise from those who have been delivered.
Psalms 76:11-12
This psalm closes with an invitation to the reader or listener. Having stated the futility of resisting God, the writer shifts to the alternatives. These verses speak of more than surrender to God; they encourage us to actively move toward God, making commitments (vows) to him and carrying them out. What was the last promise you made to God? How much progress have you made in fulfilling it?