To those who are not saved (born again) in this age of grace ie: church age, after the rapture of the body of Christ. That is who the warning is to.
It is to both Jews and Gentiles who are not saved at the Lord's coming in the clouds to receive His bride.
1 Thes 4:13] But I would not have you to be ignorant, brethren, concerning them which are asleep, that ye sorrow not, even as others which have no hope.
[14] For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with him.
[15] For this we say unto you by the word of the Lord, that we which are alive and remain unto the coming of the Lord shall not prevent them which are asleep.
[16] For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first:
[17] Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord.
[18] Wherefore comfort one another with these words.
1 Cor 15: 50] Now this I say, brethren, that flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption.
[51] Behold, I shew you a mystery; We shall not all sleep, but we shall all be changed,
[52] In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed.
[53] For this corruptible must put on incorruption, and this mortal must put on immortality.
[54] So when this corruptible shall have put on incorruption, and this mortal shall have put on immortality, then shall be brought to pass the saying that is written, Death is swallowed up in victory.
[55] O death, where is thy sting? O grave, where is thy victory?
[56] The sting of death is sin; and the strength of sin is the law.
[57] But thanks be to God, which giveth us the victory through our Lord Jesus Christ.
John.14
[1] Let not your heart be troubled: ye believe in God, believe also in me.
[2] In my Father's house are many mansions: if it were not so, I would have told you. I go to prepare a place for you.
[3] And if I go and prepare a place for you, I will come again, and receive you unto myself; that where I am, there ye may be also.
Rom 8: 32] He that spared not his own Son, but delivered him up for us all, how shall he not with him also freely give us all things?
[33] Who shall lay any thing to the charge of God's elect? It is God that justifieth.
[34] Who is he that condemneth? It is Christ that died, yea rather, that is risen again, who is even at the right hand of God, who also maketh intercession for us.
[35] Who shall separate us from the love of Christ? shall tribulation, or distress, or persecution, or famine, or nakedness, or peril, or sword?
[36] As it is written, For thy sake we are killed all the day long; we are accounted as sheep for the slaughter.
[37] Nay, in all these things we are more than conquerors through him that loved us.
[38] For I am persuaded, that neither death, nor life, nor angels, nor principalities, nor powers, nor things present, nor things to come,
[39] Nor height, nor depth, nor any other creature, shall be able to separate us from the love of God, which is in Christ Jesus our Lord.
Rev.4
[1] After this I looked, and, behold, a door was opened in heaven: and the first voice which I heard was as it were of a trumpet talking with me; which said, Come up hither, and I will shew thee things which must be hereafter.
[2] And immediately I was in the spirit: and, behold, a throne was set in heaven, and one sat on the throne.
In the tribulation, those who are not in the body of Christ (lost) will have to both believe on Christ and keep the commandments Rev 12 / 14 refusing the mark, or they will be damned (many scriptures)
Those links had all the information in expounded form, so no reason to re-plow ground that is already available for those who do not want to remain blinded or ignorant
