The Psalmist is describing his love for the Lord. In loving the Lord you keep His commandments. You just want to please Him for He is good. David is embarking upon leading the Israelite's and He is praying to the Lord all that he intends to do for the Lord. He has that zeal for the Lord.
Who can remember making a similar vow to the Lord? You know when GOD brought you out of that trial, out of misery and you said "GOD if you get me out of this I will praise Your Name, I will run on for you, I will do good and share Your Word with everyone." David was a man after GODs own heart. David wasn't perfect but he realized that when he broke a vow or sinned he sincerely asked for forgiveness and got right back in line with the Lord. He continued to praise The Lord.
Even when we break vows to the Lord, He is still faithful. Sometimes GOD doesn't want vows but He wants action. If GOD sees that you mean what you say and say what you mean, He can work with that. Be About Action.
GOD is worthy of your praise!!!
I will be careful to lead a blameless life.
I will conduct the affairs of my house with a blameless heart. Psalms 101:2
I will sing of your love and justice; to you, LORD, I will sing praise. 2 I will be careful to lead a blameless life— when will you come to me? I will conduct the affairs of my house with a blameless heart. 3 I will not look with approval on anything that is vile. I hate what faithless people do; I will have no part in it. 4 The perverse of heart shall be far from me; I will have nothing to do with what is evil. 5 Whoever slanders their neighbor in secret, I will put to silence; whoever has haughty eyes and a proud heart, I will not tolerate. 6 My eyes will be on the faithful in the land, that they may dwell with me; the one whose walk is blameless will minister to me. 7 No one who practices deceit will dwell in my house; no one who speaks falsely will stand in my presence. 8 Every morning I will put to silence all the wicked in the land; I will cut off every evildoer from the city of the LORD. Psalms 101 NIV