How could Adam sin if he was good?

When God made Adam and Eve he said that what he made was good. So, Adam was good.

"And God created man in His own image, in the image of God He created him; male and female He created them...And God saw all that He had made, and behold, it was very good. And there was evening and there was morning, the sixth day.," (Gen. 1:27,31).

However, if Adam was good how could he choose to sin?

Logically speaking we can see two truths. First, Adam was good. Second, he chose to sin. We must conclude then that being good, at least in Adam's case, does not necessitate the inability to sin.

Goodness is a quality that Adam had, but it was not holiness. Holiness belongs to God, being part of his nature, which means that God cannot sin.

However, Adam was not made holy. He was made good. Therefore, his goodness did not mean he could not fall. Adam had some help in that the devil deceived Eve. She ate the forbidden fruit and gave it to Adam, who likewise chose to rebel. So, we could say that the sin Adam committed did not arise in his own heart because his heart was good. Instead, sin arose outside of him via the serpent, through Eve, and to him.

Finally, Adam's rebellion, his choice to disobey God, resulted in sin entering the world (Romans 5:12).