It is said that this suppression of truth occurred even though what could be known about the God of creation had been made quite plain to them (Romans 1:19). Indeed, Scripture seems to indicate that Adam and Eve had a regular fellowship with the Creator, in His very presence, as it was following their eye-opening fruit-eating that “the man and his wife heard the sound of the Lord God moving about in the orchard at the breezy time of the day, and they hid from the Lord God among the trees of the orchard” (Genesis 3:8). This could be taken as an indication that such was a regular occurrence. In that time spent with Adam and Eve, it could be presumed to have been the case that it is to be understood that the covenant God made Himself and His ways and His expectations very plain to them.
Based upon that, could it not be asserted that the experience of Adam and Eve is reflected in the next verse, where Paul writes “since the creation of the world His invisible attributes---His eternal power and divine nature---have been clearly seen, because they are understood through what has been made”? (Romans 1:20a) Paul’s position is that though they would not have been able to tangibly see or feel the eternal power of the Creator God, it would most certainly have been the case that they would have been brought into an understanding of it by the very fact of their existence, along with that of the world. They would have understood that power by observing what was all around them---what had been made.
The Creator God’s divine nature would have been understood, especially by Adam, as having been made in and as the image of God, and undoubtedly having had that communicated to him as he was given the responsibility of naming all of the living creatures (according to Genesis 2:20). This was part of the exercise of the stewarding authority over the creation that had been delivered to Adam. Along with that, Adam had been placed in Eden, in the world, to care for it and to maintain it (2:15).
These two things, along with the command in regards to the tree of the knowledge of good and evil, would presumably have given Adam a vision of God’s nature, as part of the bearing of the divine image (which would seem to entail some measure of a shared nature) was the authority over and responsibility for his God’s creation. It is owing to this direct knowledge of and fellowship with the Creator God, with the explicit commands of that God and responsibilities that sprang from that knowledge and fellowship, that would have left Adam and Eve “without excuse” (Romans 1:20b) when it came time for their God to question them about the matter involving the serpent, the fruit, and their rebellion.
Following the assertion that there is a lack of any excuse, as one continues to view these verses from the first chapter of Romans through the lens of Adam and Eve and the fall, one goes on to read “For although they knew God, they did not glorify Him as God or give Him thanks, but became futile in their thoughts and their senseless hearts were darkened” (Romans 1:21). Once again, it is appropriate to here reflect on the implied fact that Adam and Eve most certainly knew the Creator God, and in a way that would have been quite unique to them alone. In the midst of this knowledge and this way of knowing, they still rebelled against Him and ate the fruit. In that, there was most certainly no glory given to their God. There was no thankfulness.