One incorrect assumption that Christians tend to make is that "in order to become I must do." This idea is especially tied to behavior. To be holy you have to behave holy. To be righteous you have to behave righteously. To be godly you have to behave godly. To be perfect you have to behave perfectly.
In Christ who you are is not based on what you do. It is all based on what Christ has done. Identity is by birth not by behavior. What did I do to become Michael Reyes? I was born into my family. Jesus tells us in John 3 that to be born into God's family we simply trust Jesus. Jesus extends His favor (grace) to us and we trust Him. From that trust in Jesus we are reborn.
Holiness, righteousness, godliness, and much more are all gifts of God to us as His new born child. They are things that cannot be earned. They can only be given. Ephesians 1:3 tells us that "God has blessed us with every spiritual blessing in Christ." When we assume that our behavior is the manner in which we attain any spiritual thing (blessings included) we miss what Christ has done for us.
Most Christians would say that godliness comes by behaving godly. God lives in us. Godliness comes by the presence of God in us which is given to us at our birth into God's family. Godliness doesn't come from moral behavior. Godliness comes from God living in you. If you don't think God living in you is enough to make you godly then you think that your own goodness, your own efforts and behavior, is what makes you godly. You think that your goodness is better than God's goodness, that you can make yourself be more godly than God can. Who or what is more godly than God?
Sadly people truly believe godly behavior is more godly than God living in them. 2 Peter 1:3 says, "God has already given us everything we need for life and godliness." Jesus is life and God is as godly as it gets. "Everything we need for life and godliness" is Christ in us! Because of what Jesus Christ has done the Christian never has to try to become. The Christian simply trusts that they already are.