Augustine (AD 354—430) equates natural law with man's Pre-Fall state.
Therefore, life according to nature is no longer possible and mankind
must instead seek salvation through the divine law and Christ’s grace.
Gratian (12th century) reconnected the concept of natural law and divine law.
“The Human Race is ruled by two things:
namely, natural law and usages (mos, moris, mores).
Natural law is what is contained in the law and the Gospel.
By it, each person is commanded to do to others what he wants done to himself
and is prohibited from inflicting on others what he does not want done to himself.”
(Decretum, D.1 d.a.c.1; ca. 1140 AD)
(Latin: ius naturale, lex naturalis)
is a philosophy asserting that certain rights
are inherent by virtue of human nature, endowed by nature
traditionally by God or a transcendent source
and that these can be understood universally
through human reason.