Admittedly, that concept doesn't pack much of a punch in political this-world terms, but the concept is that God doesn't care," with the strong though not specifically spoken implication that neither should we. Galatians is also, admittedly, speaking about Christians, not unbelievers.
The Brotherhood of Man is also implicit in the concept of the Fatherhood of God. If we are all equally children of God, whence cometh the notion that some of us are superior to others?
It should be noted that this concept is also implicit in Islam, which, however, limits it to Muslims. As, unfortunately, do some Jewish groups now and in the past limit it to the Chosen People, at least in practice. Some Christians have also limited it to Christians or even just members of their Church.
Yes, but this is not equality. God’s gifts are not distributed equally. Scripture is explicit in stating that some men and women are greater than others. Jefferson’s unqualified claim of self-evident equality for all is an instance of gross over-reaching: contrary to all evidence and the cause of great mischief.