Biblical Christianity is Paradoxical.
God's word instructs Christian belivers very clearly... The Bible clearly cautions us to hold the brethren (not a gendered term in this context) accountable to God's Word while refraining from passing judgment over those outside the Body of Christ (those who don't claim to be Christian) Judgment belongs to God alone, and we can only know that those who acknowledge and serve Christ whole heartedly are saved; the rest must be sorted by God. We must be careful not to claim we know how God will deal with them, as His word instructs us to leave that to Him. But we know that a Christian who is unrepentant: "sexually immoral, or covetous, or an idolater, or a reviler, or a drunkard, or an extortioner—" anyone who claims to walk with Christ while living in sin is doomed to be condemned, and we must hold them accountable by sending them out of our fellowship. We must judge them with a righteous judgment against the very Word of God. Of course, since we can only know (according to our faith) that salvation comes from God through His own self-sacrifice as Christ (who Himself IS God) we would run against the heart of God if we failed to invite others into our faith. Only in Christ can we be certain of salvation for anyone, so we must invite others to join us in that certainty. Apart from acknowledging and serving Christ we cannot know the outcome of eternity for another soul, but we know the outcome for the faithful because the Word of God is clear concerning His salvation offered freely through the line of David. It is a paradoxical reality that we MUST share the Gospel, offering salvation while remaining free from judgment (claiming condemnation OR salvation) for those outside the Christian faith, AND simultaneously holding eachother up to the light of scripture, judging righteously the brethren in order to effectively hold them (and ourselves) accountable. We know Christ. As a result we are condemned (cast into the waiting arms of the accuser) apart from Him who saved us, the Lord God and Father, Jesus Christ! WE cannot be saved apart from Christ once His true nature has been revealed to us (speaking specifically of those who claim Christ) What about those who don't claim Christ as Lord? We can't know how God will deal with them because He doesn't want us to worry about that. (His word instructs us to love our enemies, not judge them.) He is the only one who has made the self-sacrifice required to occupy the judgment seat of a loving God. It's a paradox, but so is the concept of the Trinity... The reality of God is immeasurably complex. Ignoring the reality of the paradox that a Being who Himself exists outside of time (without beginning or end), that is also a Man who walked on the face of the earth, and rose from the dead into an eternal state of being... requires a far too simplistic view of God. From my perspective, once you have met God you have two choices; dive deeper, or walk away. God is Love.