"For whenever Gentiles, who do not have the [Mosaic] law, by nature (φύσις) do the things of the law, they are a law to themselves, even though they do not have the [Mosaic] law. They show that the work of the [natural] law is written on their hearts, while their conscience also testifies, and their conflicting thoughts accuse or even excuse them on that day when, according to my gospel, God judges the secrets of men (τὰ κρυπτὰ τῶν ἀνθρώπων) through [the agency of] Messiah Jesus." - Romans 2:14-16
In Romans 1, Paul describes God's judgment upon obvious immoral Gentile sinners. Now in Romans 2:1-16 he discusses a second category of sinners--not-so-obvious moral Gentile sinners. Moral people from all Gentile civilisations show that the natural law is written on their heart. They have an inner conscience that evaluates the morality of what they do. God will one day, through Jesus, judge the secrets of men based on this unescapable, instinctual, inner sense of morality.
Here we see the moral argument for the existence of God. Every human has a sense of morality deep within him or her that cannot be erased. This sense of morality must have a source. Who or what could be the source other than God? Many have become theists and eventually Christians when they recognise that the moral law with them must have a source. As C. S. Lewis argued, we have "inside information" that God exists.
Father, thank you for the moral sense you have given every human being. This moral sense inside us prevents a wholesale breakdown in society. We are all judged our own conscience. You have made us moral beings, accountable to you. Remind us that one day, through Jesus, you will judge our secrets. You will find the skeletons in our closet. That's why we need your grace and forgiveness through the substitutionary death of our Lord Jesus Messiah. Thank you for the gospel that releases us from the penalty, power, and presence of sin so that we may stand in righteousness before you. We honour you and your gospel today, O God. In Jesus' name, amen.
- Jeff Coleman