Romans 2:15
Romans 2:1515So they show that the work of the law is written on their hearts, their consciences also bearing witness, and their thoughts either accusing or defending them
JWs read this verse as describing the moral instinct God placed in every human, sometimes used in ministry to argue that all people know God's basic standards even apart from formal law. The application within JW life tends to stop short of recognising the conscience-witness in non-Witnesses as evidence of God's ongoing work in them.
Paul's claim is structural — "the work of the law" is "written in their hearts" of those outside the Mosaic covenant, with their conscience "bearing witness". This is the New Testament's doctrinal warrant for taking non-Christian moral testimony seriously as the Spirit's common-grace inscription. Pair this with (the Father sends rain on the just and the unjust), (God gave the pagan nations rain and fruitful seasons), and (every good and perfect gift is from above) to build the doctrine of common grace. The "Satan also blesses worldly people" reflex, and the categorical "bad associations" reading that flows from it, both collapse against : Paul says God himself wrote the law into the conscience of Gentiles who never heard the Mosaic statutes.