Sin used to be a daily problem, like personal hygiene. You could be clean one day, but you were sure to be dirty the next. No matter how much effort you put into making sacrifices to get you right with God, there was always sure to be one more sin that created a barrier, a chasm between you and God that could never be bridged. All of that changed with Jesus, according to the seventh chapter of the letter to the Hebrews:
He is able to save forever people who approach God through him, because he lives forever to speak to God for them. He is the kind of high priest we need: holy, guiltless, pure, separated from sinners, and honoured above the heavens. He does not need to offer up daily sacrifices, like the old high priests, first for his own sins, and then for the sins of the people. He did this once for all time, when he offered up himself. The law appoints men who have weaknesses as high priests, but the oath which came after the law appoints the Son who has been made perfect forever.
God’s standard is perfection. If we want to be acceptable to God, we have to meet that standard. But under the old rules-based way of getting there, perfection can only be achieved by fully obeying all of those rules all of the time. Nobody does manage to obey all of the rules all of the time, and as a consequence, under the old system, nobody ever attains the necessary level of perfection to satisfy God’s holiness. That is why the old rule had to be set aside in favour of a better hope through which we can approach God – Jesus.