Again, what does this have to do with unwritten commands? If the Church is to follow Sola Scriptura, then what about Acts 15? Can you answer that?
Ro 2:28 For he is not a Jew, which is one outwardly ; neither is that circumcision, which is outward in the flesh: Ro 2:29
But he is a Jew, which is one inwardly ; and circumcision is that of the heart, in the spirit, and not in the letter; whose praise is not of men, but of God.
1Co 7:19
Circumcision is nothing, and uncircumcision is nothing, but the keeping of the commandments of God.
Plus circumcision is a sign of the old covenant. We have a new covenant, a new testament, and consider the old done away with.