Romans 3:25 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;
What is sought to be taught here is that only sins committed before salvation have been forgiven. First we will put this back in it's context to see if this holds up:
Romans 3:20-26
Young's Literal Translation (YLT)
20 wherefore by works of law shall no flesh be declared righteous before Him, for through law is a knowledge of sin.
Having just quoted God's judgment of man's standing before Him, Paul again seeks to clarify that the Law was meant toshow man his sin and drive him to dependance on God, namely through faith in God.
This is self-explanatory..."by works of law shall no flesh be declared righteous before Him." The Law...shows man his sin, because he cannot keep it according to a standard of perfection, and will inevitably be found guilty.
21 And now apart from law hath the righteousness of God been manifested, testified to by the law and the prophets,
Key word...righteousness. God is righteous, man is not.
22 and the righteousness of God [is] through the faith of Jesus Christ to all, and upon all those believing, -- for there is no difference,
ALL...must have faith in Christ. A general belief in God will not suffice, for God has cvommanded men to believe on His Son and to obey Him.
This does not suggest it is "to all" as well as those believing, but speaks of the same people, and states that it is to all, and upon all those believing." Only those that believe on Christ receive this imputation of righteousness.
23 for all did sin, and are come short of the glory of God --
ALL...sinned. ALL...still sin. There is not a man who has ever lived that by his own righteousness met the righteous standard of God, who never sinned, that he might not be found guilty of sin and therefore pay for that sin...with his life.
Only the Lord, God manifest in the flesh, Emmanuel, God with us...lived holy, harmless, undefiled, and separate from sinners.
He alone is worthy, and can stand in the place of the sinner, to die in his place that the debt our sin incurs might be paid in full.
24 being declared righteous freely by His grace through the redemption that [is] in Christ Jesus,
The declaration of the sinner being righteous occurs upon salvation, else, they could not then become children of God. It is by grace through the faith in Christ that is many times taught in scripture. It is not through works of any kind, for if it were it would not be the righteousness of Christ declared, but the righteousness of the sinner declared, and one can hardly read this chapter without understanding that scripture makes it clear there is none righteous...no not one.
Declared righteous...
freely through His grace.
25 whom God did set forth a mercy seat, through the faith in his blood, for the shewing forth of His righteousness, because of the passing over of the bygone sins in the forbearance of God --
What are the "bygone sins?" They include the sins of the Old Testament saints, who were not made perfect, and could not be made perfect until Christ died in their place. We say rightly that they were "saved by grace" as well, but even as we all who are saved are known to God before we are saved, even so they could not be made perfect until their sin had been atoned for:
Hebrews 11:39-40
Young's Literal Translation (YLT)
39 and these all, having been testified to through the faith, did not receive the promise,
40 God for us something better having provided, that apart from us they might not be made perfect.
...and this did not occur until Christ died for them.
26 for the shewing forth of His righteousness in the present time, for His being righteous, and declaring him righteous who [is] of the faith of Jesus.
THat the two ages are contrasted is clear in this verse. While the Old Testament saints had a hope in Messiah, their expectation was temporal. Specific faith in Christ for salvation is implied in the Old Testament, but we can see even in the Disciples before Pentecost and the coming of the Comforter...they did not understand.
Before the Cross they preached the "Kingdom of Heaven" and the "Kingdom of God." After the Cross they went back to their previous lives.
Afte Pentecost...
they preached the Gospel of Jesus Christ in the power of the Holy Spirit, the Comforter.
At this time it is the righteousness of Christ we preach...not the righteousness of the sinner...which has never met more than a human, temporal standard.
Now let's consider a few verses that teach the righteousness of Christ:
Romans 4:5-6
Young's Literal Translation (YLT)
5 and to him who is not working, and is believing upon Him who is declaring righteous the impious, his faith is reckoned -- to righteousness:
6 even as David also doth speak of the happiness of the man to whom God doth reckon righteousness apart from works:
It is not a matter of the sinner being righteous, it is a matter of God declaring him righteous, and this apart from his works. We see clearly that it is the unrighteous that are declared righteous...not those that have stopped sinning. Those who feel they have cleaned themselves up and are therefore worthy of the imputation of the righteousness of Christ fail before they begin, for the word of God will teach them of their sin.
Romans 5:17-18
Young's Literal Translation (YLT)
17 for if by the offence of the one the death did reign through the one, much more those, who the abundance of the grace and of the free gift of the righteousness are receiving, in life shall reign through the one -- Jesus Christ.
18 So, then, as through one offence to all men [it is] to condemnation, so also through one declaration of `Righteous' [it is] to all men to justification of life;
Through Christ, not works which we have done.
Romans 10:3
Young's Literal Translation (YLT)
3 for not knowing the righteousness of God, and their own righteousness seeking to establish, to the righteousness of God they did not submit.
Israel thought they could attain to the righteous standard of God through keeping the Law.
Romans 10:4
Young's Literal Translation (YLT)
4 For Christ is an end of law for righteousness to every one who is believing,
"Everyone believing." Belief is obedience to the Gospel, and means of beiong declared righteous through the imputation of the righteousness of Christ.
All aspects of salvation are through Christ...alone:
1 Corinthians 1:30
Young's Literal Translation (YLT)
30 and of Him ye -- ye are in Christ Jesus, who became to us from God wisdom, righteousness also, and sanctification, and redemption,
To be continued...