So what then of the righteous Jew? The righteous Muslim? The Hindu? The (gasp) righteous atheist?
They need to trust Jesus (or Yeshua) as their Messiah or Savior.
Now, a lot of that responsibility falls on the church (those who are already saved.) First, we need to proclaim the Gospel in the demonstration of the Spirit and power, not some theological head knowledge. Jesus called it the 'Gospel of the Kingdom'.
Then, we need to back it up with a sacrificial life of service. There are too many people giving lip service to God and not much else. No wonder it's not convincing.
And by the way, Jesus said He wasn't coming back until the whole world has heard this. (Matt 24:14)
It's not so much the unbeliever's fault as it is the church's. Now, once someone has made the decision to reject Jesus Christ, the responsibility falls upon his own head.
So-called "Righteousness" will be Judged.
No one can assume to know the extent of God's mercy in the Afterlife -- least of all we mere mortals -- but the Bible is clear about the terms of guaranteed Salvation by the Blood of the Lamb.