The goal of Christians is to be conformed to the image of Christ. The reason we ask “What would Jesus do?” is to put ourselves in the right frame of mind to be Christ-like in our decision making (Philippians 2). We know from reading the Gospels and the letters of Paul that we are to think like Christ, to have the heart and mind of a servant, to be humble, to love as Christ loved, and so forth. Like John the Baptist we must make less of ourselves and more of Christ. Realizing that we can never become perfectly like Christ, the goal is to continuously work at it. As we get closer and closer, others should be able to see Christ in us. They were called Christians first at Antioch why? Because the followers of Christ at Antioch sounded and acted like the one they were following.
Ephesians 3 mentions one way to be Christ-like, which I had never noticed before. Read Colossians 1, noting verse 19 that says “For in him [Christ] all the fullness of God was pleased to dwell…” Jesus was incarnate deity, the person of God robed in a body of flesh. One aspect of Jesus Christ is that he was full of God. Now look at Ephesians 3, a short chapter in which Paul reveals the mystery of the Gospel. In particular:
For this reason I bow my knees before the Father, from whom every family in heaven and on earth is named, that according to the riches of his glory he may grant you to be strengthened with power through his Spirit in your inner being, so that Christ may dwell in your hearts through faith—that you, being rooted and grounded in love, may have strength to comprehend with all the saints what is the breadth and length and height and depth, and to know the love of Christ that surpasses knowledge, that you may be filled with all the fullness of God. -Ephesians 3:14-19 ESV
There are many things we can choose to fill ourselves with; Paul says we should be full of God.