Adam and Eve's provision in the garden of Eden was God's provision of grace for mankind.
Gen.3: 15 speaks about the beginning of the dispensation of grace:
"And I will put enmity between you and the woman, and between your seed and her Seed; He will bruise your head, and you shall bruise His heel." (Gen. 3:15).
This promise was fulfilled by the Lord Jesus Christ:
"For this is My blood of the new covenant, which is shed for many for the remission of sins." (Mat.26: 28).
God's grace and God's judgment was manifested by God's shutting of the door of the ark - sealing grace for the redeemed family within, and judgment for all the families outside.
God's grace was manifested through the birth of Isaac, and again when through the intercession of Moses, God relented of the destruction of all Israel. And God's grace was manifested through Cyrus of Persia's edict to release the captive Jews and by Artaxerxes Longimanus's later edict to reconstruct the walls of Jerusalem - the beginning of the 70 "weeks" of Daniel's 70 "weeks" prophecy.
The Dispensation of Law, said Paul, was temporary - and Paul said that the Law was ADDED:
"Why then the Law? It was added because of transgressions, until the Seed should come to those to whom it had been promised, being ordained through angels in the Mediator's hand." (Gal.3: 19).
What was the Law added to? And when did "the Dispensation of grace" REALLY begin?