They always obeyed...Paul commended

Philippians 2:12-13...Wherefore, my beloved, as ye have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling. For it is God which worketh in you both to will and to do of his good pleasure. 

Christians have the power to obey God. Not a struggle to obey God; its the blessing of the Christian life where the Holy Spirit governs your life. God does the work within as a result of your faith in Christ. Therefore this new creation is made right to do right in everyday life. Obeying God is the result of the Saving Grace of God in the heart of a believer in Christ...

2 Corinthians 5:21...For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him.