"Right and wrong clearly exist, and are neither subjective preferences nor socio-biological pressures which lack any real authority over us. Everybody recognizes that there is a Moral Law above human beings, and nobody can consistently live in total denial of this fact.
But where
does this standard come from?
God’s eternal and unchanging holy nature
provides the best explanation, because He is the summum bonum (greatest good) and, as Creator, has authority to rule over His creatures.
He has written His Law on our hearts (Which shew the work of the law written in their hearts, their conscience also bearing witness, and their thoughts.... Romans 2:15)."
CMI