The Justifier of him that believth on Jesus !
Rom 3:26
To declare, I say, at this time his righteousness: that he might be just, and the justifier of him which believeth in Jesus.
That He might be Just and the Justifier of him which is believing on Jesus !
Now one of the meanings of this verse is that all who come to be believers in Jesus, its because God's Law and Justice has been satisfied for them by Jesus, that one who came to save His People from their sins Matt 1:21; and so they become believers because what Christ did for them is made known to them by the Spirit, for the Spirit takes what is Christ's accomplishment for them, and shows it to them Jn 16:14
14 He shall glorify me: for he shall receive of mine, and shall shew it unto you.[The Church]
Since Christ has died for them, and satisified God's Law and Justice, paid their sin debt in full, they are given the right and privilege of believing on Him Phil 1:29
29 For unto you it is given in the behalf of Christ, not only to believe on him, but also to suffer for his sake;
And of course those who do not believe on Jesus for Salvation, its simply because they were not of His Sheep which He died for Jn 10:26
26 But ye believe not, because ye are not of my sheep, as I said unto you.
Non sheep do not have that privilege given to them Matt 13:11
11 He answered and said unto them, Because it is given unto you to know the mysteries of the kingdom of heaven, but to them it is not given.
Once again, those for whom Christ died, He for them only satisfied God's Law and Justice in His Sufferings and Death , which all the wrath due to their sins, and also fulfilling its Righteousness, so Faith is given to them through the Righteousness of God and their Saviour Jesus Christ 2 Pet 1:1
Simon Peter, a servant and an apostle of Jesus Christ, to them that have obtained like precious faith with us through the righteousness of God and our Saviour Jesus Christ:
All who come to believe on Jesus was because they were Justified before God by His Death and Imputed Righteousness !