The “one rule” was ultimately for our good not intended as a restriction. Staying away from the tree of the knowledge of good and evil was the ultimate protection for the peace of mankind. It only looks like a restriction from this side of the fall. We are so used to having our own way that we refuse to see the supremacy of walking under the protection of His presence. In the bliss of His perfect will for us.
To step inside grace we do need to surrender our will to His. It is a complete change in our thinking to agree with grace that we don’t need to work to be perfect and acceptable before we can get near Papa God. Grace makes us righteous and clean by none of our own efforts, it is amazing, yes truly unbelievable, but that is exactly what we must believe in to transition from death into life.
The one rule turns out to be that we must fall under grace, setting aside all our works to accept Jesus’ finished work of the cross. Thereby holding up to ridicule all the religious systems mankind had created by conquering death and the grave. It’s as simple as changing our thinking, which is the definition of repentance. Not parading in sack cloth and ashes or crawling through the streets on bloody knees. Just a divinely inspired change of mind, that the truth is, we are indeed saved by the finished works of Jesus and nothing else.