(Note: this sermon has a short blank portion-scroll to 1:10 to start listening).
Psalm 101, a Psalm of David, are the vows of a holy king. David, as King of Israel, served not as a high king but a vassal to the true King. This song was his pledges before the Lord God Almighty.
How does this apply to us as servants of God. Heidelberg Catechism Lord's Day 12 tells us of the meaning of Christ being God's anointed, the Christ. Then in the 2nd part of the Lord's Day we ask why we are called Christians. The answer reminds us that, in faith, we are members of Christ and partake of His anointing. As such, through faith, David's vows in Psalm 101 should also be ours, to serve our true high King.
I will sing of mercy and justice; ‚Äč‚ÄčTo You, O LORD, I will sing praises. ‚Äč‚Äč‚ÄčI will behave wisely in a perfect way. ‚Äč‚ÄčOh, when will You come to me? ‚Äč‚ÄčI will walk within my house with a perfect heart. ‚Äč‚ÄčI will set nothing wicked before my eyes; ‚Äč‚ÄčI hate the work of those who fall away; ‚Äč‚ÄčIt shall not cling to me. ‚Äč‚ÄčA perverse heart shall depart from me; ‚Äč‚ÄčI will not know wickedness. ‚Äč‚ÄčWhoever secretly slanders his neighbor, ‚Äč‚ÄčHim I will destroy; ‚Äč‚ÄčThe one who has a haughty look and a proud heart, ‚Äč‚ÄčHim I will not endure. ‚Äč‚ÄčMy eyes shall be on the faithful of the land, ‚Äč‚ÄčThat they may dwell with me; ‚Äč‚ÄčHe who walks in a perfect way, ‚Äč‚ÄčHe shall serve me. ‚Äč‚ÄčHe who works deceit shall not dwell within my house; ‚Äč‚ÄčHe who tells lies shall not continue in my presence. ‚Äč‚ÄčEarly I will destroy all the wicked of the land, ‚Äč‚ÄčThat I may cut off all the evildoers from the city of the LORD.