Jesus brought grace when he came in the flesh, but example of grace was in the days of Noah. But Noah found grace in the eyes of the LORD. (Genesis 6:8), And Noah and his family was saved. Now Paul said in (Rom. 3:23-25) (v.23) For all have sinned, and come short of the glory of God. (v.24) Being justified freely by his grace through the redemption that is in Christ Jesus: (v.25) Whom God hath set forth to be a propitiation through faith in his blood, to declare his righteousness for the remission of sins that are past, through the forbearance of God. So the bible tells you to repent and be baptized in the name of Jesus for the remission of sins, and ye shall receive the gift of the Holy Ghost." (Acts 2 :36-38). And by doing so you come up under his precious blood and then you are saved from your sins that are past, not present or future sins but for sins that are past. We were all locked under death by Adam’s sin, even the second death. But when Jesus became (he was God in the beginning) man and died for the sins of the world, he gave us access back to the tree of life (himself) which Adam had caused us to lose. That’s what grace is, our free gift our access back to the tree of life but that’s another lesson for another time.
So by coming under the blood of Jesus you are saved from your past sins. And if you are saved now, it is on a day to day basis. Because for all have sinned, and come short of the glory of God (Romans 23:3), and if you continue to live you will sin again. It is the willful sinning that you need to put in check. For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins, but a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries. (Hebrew 10: 26, 27)