Romans 1:19 - Matthew Poole's English Annotations on the Holy Bible

That which may be known of God; or, that which is knowable of God, viz. by the light of nature. The apostle, by a prolepis, prevents an objection which some might make in excuse of the Gentiles: how could they sufficate or suppress the truth, seeing they wanted the Scripture, and were without the knowledge of it? To this he answers, that they were not wholly without knowledge, for that which might be known of God was manifest in them, and revealed to them. Is manifest in them, i.e. in their heart and minds; see Romans 2:15: or, to and among them; as appears by many of their learned writers, who have left behind them many clear discourses, and wise essays and sayings, about this matter, though they themselves did act contrary thereunto. For God hath showed it unto them; i.e. as before, by the light of nature in their consciences, or by the consideration of the creatures, as it follows in the next verse.