The problem that all of us face as believers is that even our best works are tainted with sin, with impure motives and designs. How can we ever truly please God with our feeble attempts at good?
There is great liberation in knowing that God views not only our past rebellion but all of our works through the lens of his Beloved Son. The blood of Jesus cleanses us even as we are walking "in the light" (1 John 1:7). We can please him!
The Westminster Confession states in Chapter 16...
VI. Notwithstanding, the persons of believers being accepted through Christ, their good works also are accepted in Him; not as though they were in this life wholly unblamable and unreproveable in God's sight but that He, looking upon them in His Son, is pleased to accept and reward that which is sincere, although accompanied with many weaknesses and imperfections. [References: Eph 1:6; 1 Pet 2:5; Ex 28:38; Gen 4:4; Heb 11:4; Job 9:20; Ps 143:2; Heb 13:20-21; 2 Cor 8:12; Heb 6:10; Matt 25:21-23]
The Father looks upon us as being united with his Son. He is pleased with our faith, love, gratitude, obedience to his Word, and desires to honor him -- however weak or small these may be.
By the way, John Frame is helpful in explaining what are the criteria for good works, in The Doctrine of the Christian Life, pp. 27-28...
- Right motive (faith working through love)
- Right standard (the Word of God)
- Right goal (to glorify God)
Right motive: "But whoever has doubts is condemned if he eats, because the eating is not from faith. For whatever does not proceed from faith is sin." (Romans 14:23) "For in Christ Jesus neither circumcision nor uncircumcision counts for anything, but only faith working through love." (Galatians 5:6) "And he said to him, 'You shall love the Lord your God with all your heart and with all your soul and with all your mind.' This is the great and first commandment. And a second is like it: 'You shall love your neighbor as yourself.'" (Matthew 22:37-39)
Right standard: "Whoever has my commandments and keeps them, he it is who loves me. And he who loves me will be loved by my Father, and I will love him and manifest myself to him." (John 14:21) "So Jesus said to the Jews who had believed in him, 'If you abide in my word, you are truly my disciples, and you will know the truth, and the truth will set you free.'" (John 8:31-32) "Everyone who makes a practice of sinning also practices lawlessness; sin is lawlessness." (1 John 3:4)
Right goal: "So, whether you eat or drink, or whatever you do, do all to the glory of God." (1 Corinthians 10:31) "...to the praise of his glorious grace, with which he has blessed us in the Beloved." (Ephesians 1:6) "And whatever you do, in word or deed, do everything in the name of the Lord Jesus, giving thanks to God the Father through him." (Colossians 3:17)