The Old Testament tabernacle was a mirror image of the tabernacle in Heaven where Christ would someday make the atonement with His shed blood. Jesus used His own blood which was shed on the cross to atone for our sins.
1 Peter 1:18,19
Forasmuch as ye know that ye were not redeemed with corruptible things, as silver and gold, from your vain conversation received by tradition from your fathers, But with the precious blood of Christ, as of a lamb without blemish and without spot
Now where remission of these is, there is no more offering for sin.Having therefore, brethren, boldness to enter into the holiest by the blood of Jesus, By a new and living way, which he hath consecrated for us, through the veil, that is to say, his flesh;
And having an high priest over the house of God. Let us draw near with a true heart in full assurance of faith, having our hearts sprinkled from an evil conscience, and our bodies washed with pure water
Wherefore he is able also to save them to the uttermost that come unto God by him, seeing he ever liveth to make intercession for them.
For such an high priest became us, who is holy, harmless, undefiled, separate from sinners, and made higher than the heavens. Who needeth not daily, as those high priests, to offer up sacrifice, first for his own sins, and then for the people’s: for this he did once, when he offered up himself.
This is important to understand; Jesus died and atoned for our sins ONCE. IT IS FINNISHED!
The cross was the instrument used to bring death to the messiah and shed his blood. It is not the cross that saves but rather the blood of the lamb that was shed on the cross. The cross represents surrender to the will of God. Even as Jesus surrendered his will to the father to go to the cross in order to shed his blood for the sins of the world.
Do not forget that it is the blood of the lamb that takes away our sin!
Saying, This is the blood of the testament which God hath enjoined unto you.
Moreover he sprinkled with blood both the tabernacle, and all the vessels of the ministry.
And almost all things are by the law purged with blood; and without shedding of blood is no remission. It was therefore necessary that the patterns of things in the heavens should be purified with these; but the heavenly things themselves with better sacrifices than these.
For Christ is not entered into the holy places made with hands, which are the figures of the true; but into heaven itself, now to appear in the presence of God for us:
Nor yet that he should offer himself often, as the high priest entereth into the holy place every year with blood of others;
For then must he often have suffered since the foundation of the world: but now once in the end of the world hath he appeared to put away sin by the sacrifice of himself.
And as it is appointed unto men once to die, but after this the judgment:
So Christ was once offered to bear the sins of many; and unto them that look for him shall he appear the second time without sin unto salvation
We can never earn salvation because only the blood of a perfect lamb without sin could atone for our sin! You can never win approval from God! Those whom he calls he also equips with his Spirit to do HIS WORKS!
And you hath he quickened, who were dead in trespasses and sins; Wherein in time past ye walked according to the course of this world, according to the prince of the power of the air, the spirit that now worketh in the children of disobedience: Among whom also we all had our conversation in times past in the lusts of our flesh, fulfilling the desires of the flesh and of the mind; and were by nature the children of wrath, even as others. But God, who is rich in mercy, for his great love wherewith he loved us, Even when we were dead in sins, hath quickened us together with Christ, (by grace ye are saved;) And hath raised us up together, and made us sit together in heavenly places in Christ Jesus: That in the ages to come he might shew the exceeding riches of his grace in his kindness toward us through Christ Jesus. For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast. For we are his workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them.