Good Things To Come
The Son of God was sacrificed for the forgiveness of the sins of repentant sinners (see Baptism Of Fire). It was a Sacrifice of an absolutely perfect "Lamb of God" that will not be repeated. His Sacrifice was "once and for all," and so too is the opportunity, when it comes, to accept or reject it.
"6:4 For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of The Holy Ghost, 6:5 And have tasted the good word of God, and the powers of the world to come, 6:6 If they shall fall away [see Reprobate], to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame" (Hebrews 6:4-6 KJV).
"Christ being come an high priest of good things to come"
Much of Bible History was actually Prophecy that portrayed the coming of the Messiah with a single purpose and meaning.
"9:11 But Christ being come an high priest of good things to come, by a greater and more perfect tabernacle, not made with hands, that is to say, not of this building; 9:12 Neither by the blood of goats and calves, but by his own blood [see Why Blood?] he entered in once into the holy place, having obtained eternal redemption for us. 9:13 For if the blood of bulls and of goats, and the ashes of an heifer sprinkling the unclean, sanctifieth to the purifying of the flesh: 9:14 How much more shall the blood of Christ, who through the eternal Spirit offered himself without spot to God, purge your Conscience from dead works to serve the living God?
9:15 And for this cause he is the mediator of the new testament, that by means of death, for the redemption of the transgressions that were under the first testament, they which are called might receive the promise of eternal inheritance [see Spiritual Adoption].
9:16 For where a testament is, there must also of necessity be the death of the testator.
9:17 For a testament is of force after men are dead: otherwise it is of no strength at all while the testator liveth. 9:18 Whereupon neither the first testament was dedicated without blood. 9:19 For when Moses [see also The Education Of Moses] had spoken every precept to all the people according to the law, he took the blood of calves and of goats, with water, and scarlet wool, and hyssop, and sprinkled both the book, and all the people, 9:20 Saying, This is the blood of the testament which God hath enjoined unto you. 9:21 Moreover he sprinkled with blood both the tabernacle, and all the vessels of the ministry. 9:22 And almost all things are by the law purged with blood; and without shedding of blood is no remission.
9:23 It was therefore necessary that the patterns of things in the heavens should be purified with these; but the heavenly things themselves with better sacrifices than these. 9:24 For Christ [see The Anointed One] is not entered into the holy places made with hands, which are the figures of the true; but into heaven itself, now to appear in the presence of God for us: 9:25 Nor yet that he should offer himself often, as the high priest entereth into the holy place every year with blood of others; 9:26 For then must he often have suffered since the foundation of the world: but now once in the end of the world hath he appeared to put away sin by the sacrifice of himself. 9:27 And as it is appointed unto men once to die, but after this the judgment [see When Will You Be Judged?]: 9:28 So Christ was once offered to bear the sins of many; and unto them that look for him shall he appear the second time without sin unto salvation." (Hebrews 9:11-28 KJV)
Fact Finder: What makes conversion possible? Regardless of when the enlightening happens, are there any "second chances"?
See The Cure For The Carnal Mind and No U Turns On The Road To Life