One of the mark of a genuine believer is the delight in God's word and fighting all the Bible calls sin. I'm saying this as one because the two is so connected that it is impossible to have one but not have the other. These are two sides of one coin. Clearly stated in this Psalm how it works. We are to store up God's word in our hearts so that we might not sin against God (Psalm 119:11).
It is by memorizing promises in the Bible that enables us to walk uprightly. Those promises are the words that will be used by the Holy Spirit to remind us in specific struggles that we have everyday. So we pray that God will teach us his ways through the Scriptures (Psalm 119:12).
We know how to enjoy all the things that he provides and verse 14 tells us that we are able to enjoy his promises too by his enabling power (Psalm 119:14). Let us take our part in this fight. Let us meditate on God's word, day and night. Let us fix our eyes on God's promises. Let us not forget his word as we fight sin. It may be hard but God is with us, who can be against us.
In Christ Jesus, we have the confidence that the promises of God is for us also. We have the boldness to look at our sins and say "You don't get the final word over my life, I am a new creation and my creator have won it on the cross go where you ought to be. By his grace I will overcome!"
You are God's, so, kill sin.