Martin Luther wrote the following:
Oh, it is a living, busy, active and mighty thing, this faith. It is impossible for it not to be doing good works incessantly. It does not ask whether good works are to be done, but before the question is asked, it has already done them, and is constantly doing them. Whoever does not do such good works, however, is an unbeliever….Faith is a living, daring confidence in God’s grace, so sure and certain that the believer would stake his life on it a thousand times. This knowledge of and confidence in God’s grace makes [people] glad and bold and happy in dealing with God and with all creatures. And this is the work which the Holy Spirit performs in faith. Because of it, without compulsion [Christians are] ready and glad to do good to everyone, to serve everyone, to suffer everything, out of love and praise to God who has shown [them] this grace. Thus it is impossible to separate works from faith, quite as impossible to separate heat and light from fire.
Source: Martin Luther, “Preface to St. Paul’s Epistle to the Romans,” in Luther’s Works, Vol. 35 (Philadelphia: Fortress Press, 1960), pp. 370-71.
I actually read this quote in another book – Power Surge by Michael Foss (pg. 82-83).
Luther pretty much hits the mark on how to tell if someone has been transformed by Jesus and is living out new life in Christ.
Does this mean this person is perfect – hardly. However, I think it means that even though a person will fall and fail and sin, they will confess and keep seeking and receiving forgiveness, and get up and try again.
You might notice a few things that are absent from Luther’s description. You might notice that a Christian isn’t someone who claims the label of Christian and then supports policies that go against what it means to be a Christian. You might notice that a Christian isn’t someone who claims the label of Christian and then supports behavior that diminishes and dehumanizes other human beings. You might notice that a Christian isn’t someone who claims the label of Christian and then lays responsibility for action on others, on government, or non-profits. You might notice that a Christian isn’t someone who claims the label of Christian and then puts their faith and trust in a politician to lead the charge for good works.
A Christian isn’t called to wait for someone else to get good works started. They are called to respond to the faith they have been given, and to start carrying out that faith – even if they are the only one.