To whom is 1 Cor. written?
1 Corinthians 1:2
(2) To the church of God in Corinth, to those sanctified in Christ Jesus and called to be his holy people, together with all those everywhere who call on the name of our Lord Jesus Christ—their Lord and ours:
To the "church of God in Corinth" and specifically "his holy people". That is the context of the entire letter.
That doesn't stop it from talking *about* other peoples, other churches, angels, demons, false teachers, prostitutes, drunks, Apollos, Peter, all mankind & many other topics that are not talking *about* the "church of God which is at Corinth". Does it? Obviously not. So how are your quoted verses of 1 Corinthians 1-2 relevant to the topic?
In the passage which you are quoting parts out-of-context Paul says "we are co-workers in God's service; God's field, God's building."
There is no mention of such in all these verses of 1 Corinthians 3:
10b But let every man take heed how he buildeth thereupon.
11 For other foundation can no man lay than that is laid, which is Jesus Christ.
12 Now if any man build upon this foundation gold, silver, precious stones, wood, hay, stubble;
13 Every man's work shall be made manifest: for the day shall declare it, because it shall be revealed by fire; and the fire shall try every man's work of what sort it is.
14 If any man's work abide which he hath built thereupon, he shall receive a reward.
15 If any man's work shall be burned, he shall suffer loss: but he himself shall be saved; yet so as by fire.
That says "every man", not "every saint", not "every believer", not "every church member", not "every Christian", not "everyone of us", and not "every labourer", etc.
Paul is not saying that all mankind are "
co-workers in God's service"
Verses 16-17 of the context immediately following v.15 speaks of those who are not saved in 17a:
(15) If any man's work shall be burned, he shall suffer loss: but he himself shall be saved; yet so as by fire.
(16) Know ye not that ye are the temple of God, and that the Spirit of God dwelleth in you?
(17) If any man defile the temple of God, him shall God destroy; for the temple of God is holy, which temple ye are.
Compare:
1 Cor.5:5 To deliver such an one unto Satan for the destruction of the flesh, that the spirit may be saved in the day of the Lord Jesus.
And therefore, in context, 3:15 is also referring to those who are not saved, but become saved "as by fire".
All mankind are not co-workers in God's service, building on the foundation of Jesus Christ, vs. 11.
Verse 11 says that "no one" can lay any foundation other than the one that has been laid which is Jesus Christ. The words "no one" are not limited to the saints in Corinth, but refer to all mankind. This is the last reference identifying any group of people in the next several verses leading up to v.15. Thus the most immediate prior context reference and the more immediate following context both support the view that v.15 refers to the unsaved being saved.
All mankind does not have the spirit of God dwelling in them. Vss. 13-15 cannot be saying all mankind will be saved when vs. 17 says that any man who defiles the temple of God will be destroyed not saved.
The destroyed can be saved, as Corinthians clearly shows:
1 Cor. 5:4 In the name of our Lord Jesus Christ, when ye are gathered together, and my spirit, with the power of our Lord Jesus Christ,
1 Cor. 5:5 To deliver such an one unto Satan for the destruction of the flesh, that the spirit may be saved in the day of the Lord Jesus.
Jesus is the Light that lightens every man (Jn.1:9). Human beings were made in God's image & likeness. They are temples made by God:
Acts 17:22 Then Paul stood in the midst of Mars' hill, and said, Ye men of Athens...
24...[the] Lord of heaven and earth, dwelleth not in temples made with hands;...25...
he giveth to all life, and breath, and all things;... 28 For in him we live, and move, and have our being; as certain also of your own poets have said, For we are also his offspring. 29 Forasmuch then as we are the offspring of God...
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Scholar's Corner: The Center for Bible studies in Christian Universalism
"...it doesn't say what most evangelizers of hopelessness want it to say in that regard either."
"It is false, he maintained, to translate that phrase as "everlasting punishment," introducing into the New Testament the concept found in the Islamic Quran that God is going to torture the wicked forever."