Youre looking at salvation (regeneration) as some one time point decision - POOF experience. Regeneration is a process which encompasses MANY individual steps. Granted, sometimes these steps may appear to us as a one time event but this is not always the case.
There are two cases in the Bible that talks about the regeneration experience in slow motion (over time). One is Abraham and the other is Cornelius. Their experience is almost exactly the same.
Step 1 Gods Grace in Revealing Himself Now the Lord said to Abram, Go forth from your country, and from your relatives and from your fathers house, to the land which I will show you; and I will make you a great nation, and I will bless you, and make your name great; and so you shall be a blessing; Gen 12:1-2
Step 2 Mans Repentance he [Abram] built an altar to the Lord and called upon the name of the Lord Gen 12:8
Step 3 Mans Faith in God-Saved by Faith then he [Abram] believed in the Lord; and He reckoned it to him as righteousness. Gen 15:6
Step 4 Mans Obedience to Gods Commands-Saved by Works By Myself I have sworn, declares the Lord, because you have done this thing and have not withheld your son, your only son, indeed I will greatly bless you, and I will greatly multiply your seed as the stars of the heavens Gen 17:16-17
You would have Abraham regenerated in Step 3 when he believed. But that doesnt explain how Abraham was justified by his works as James points out which happened many years later. jkl1122 would have us believe regeneration occurs at Step 4 (or Step 2) but that doesnt explain Romans (Step 3).
Regeneration is a process initiated by God. Step 1 is that God reveals Himself to us and blesses us. Once God initiates the process, as with the case of Abraham, He will protect us until the regeneration process is completed.
This raises an important point. Does God reveal Himself to everyone? This is not what the scriptures say.
All things have been handed over to Me by My Father; and no one knows the Son except the Father; nor does anyone know the Father except the Son, and anyone to whom the Son wills to reveal Him. Matt 11:27 (also Luke 10:22)
And Jesus said to him, [Peter] Blessed are you, Simon Barjona, because flesh and blood did not reveal this to you [Jesus is the Christ], but My Father who is in heaven. Matt 16:17
Sanctification comes in three stages.
First, salvation by faith which is an event (Jn.3), then spiritual growth which is a process (Heb.5) then ultimate sanctification when we receive our resurrection bodies (Rom.8).
What you see in Rom.4 is Abraham being saved, in James 5 his growth into 'friend of God' and hero of the faith. The Justification of Rom.4 is for salvation and to God, the Justification in James 2 is to be seen by men as proof of your salvation.
As for God revealing Himself to everyone read Psa.19 and Rom.1.