Since God provided for the forgiveness of sins in the Old Testament, why do we need Jesus?
There are several distinct aspects that need to be considered.
- Forgiveness for relationship.
- Forgiveness for judicial sin debt.
- The receiving of eternal life.
The idea that the forgiveness is relational can be supported by comparing the following;
Leviticus 16:30 For on that day shall the priest make an atonement
for you, to cleanse you, that ye may be clean from all your sins
before the LORD.
1 John 1:9 If we confess our sins, he is faithful and just to forgive
us our sins, and to cleanse us from all unrighteousness.
The emphasis on "cleansing" in both verses can be seen to lend support that the "forgiveness" being discussed is not a judicial / salvation forgiveness, but a restoration of relationship forgiveness.
The 1 John verse indicates that Christians still need to be cleansed for a close relationship with their Savior. However, New Testament Christians at the moment they are saved are sealed with the Holy Spirit, have eternal life, and have a judicial / salvation forgiveness of their sins.
John 5:24 Verily, verily, I say unto you, He that heareth my word,
and believeth on him that sent me, hath everlasting life, and shall
not come into condemnation; but is passed from death unto life.
Ephesians 1:13 In whom ye also trusted, after that ye heard the word
of truth, the gospel of your salvation: in whom also after that ye
believed, ye were sealed with that holy Spirit of promise,
Colossians 2:13 And you, being dead in your sins and the
uncircumcision of your flesh, hath he quickened together with him,
having forgiven you all trespasses;
The New Testament Christian gets everything at once. The Old Testament believer accumulated throughout his life. His forgiveness of sins was also a result of faith, however, he would not receive eternal life until his resurrection.
Romans 4:5-8 But to him that worketh not, but believeth on him that
justifieth the ungodly, his faith is counted for righteousness. Even
as David also describeth the blessedness of the man, unto whom God
imputeth righteousness without works, Saying, Blessed are they whose
iniquities are forgiven, and whose sins are covered. Blessed is the
man to whom the Lord will not impute sin.
Daniel 12:2 And many of them that sleep in the dust of the earth
shall awake, some to everlasting life, and some to shame and
everlasting contempt.
The reason Jesus is needed is that without Jesus there would be no way to impart eternal life.
1 Corinthians 15:22 For as in Adam all die, even so in Christ shall
all be made alive.
In addition, it would not be possible to impute righteousness or offer forgiveness unless a payment had been made.
1 John 2:2 And he is the propitiation for our sins: and not for ours
only, but also for the sins of the whole world.