So let's first make sure that we mean the same thing with our terms:
- When I hear "Conditional election" what I believe the phrase means ... 'the belief that God chooses for eternal salvation those whom he foresees will have faith in Christ, emphasizing the importance of a person's free will'. Is that what YOU mean by Conditional Election?
- When I hear "Unconditional election" what I believe the phrase means ... 'the belief that God does not foresee an action or condition on our part that induces Him to save us, rather God sovereignly decides to save whomever He is pleased to save'. Is that what YOU understand Unconditional Election to mean?
Assuming that we mean the same thing by "conditional" and "unconditional", let us move on to examine 2 Thessalonians 2:13:
The Paragraph [2 Thessalonians 2:13-15 NASB]:
13 But we should always give thanks to God for you, brethren beloved by the Lord, because God has chosen you from the beginning for salvation through sanctification by the Spirit and faith in the truth. 14 It was for this He called you through our gospel, that you may gain the glory of our Lord Jesus Christ. 15 So then, brethren, stand firm and hold to the traditions which you were taught, whether by word [of mouth] or by letter from us.
2 Thessalonians 2:13 starts out "we should always give thanks to God for you". While I am always in favor of giving thanks to God as a general principal, both for who God is and for what God has done, why does Paul start out this particular verse giving God thanks for 'THEM'. If your interpretation is correct, 'they' should give thanks to God for their forgiveness in Jesus, but all God has done was to acknowledge those that loved God (and damn those that do not love God) with this act of God being fully CONDITIONAL upon 'their' faith in the truth. For what is Paul thanking God: not rejecting people in spite of their faith?
It continues "God has chosen you from the beginning" and You mention that 'God has chosen' but neglect 'from the beginning'. It is clearly at least POSSIBLE that Paul is thankful to God for choosing 'them' (individually and specifically) from the 'beginning' ... which could be the same 'beginning' as John 1:1. I am not arguing that this is the only possible interpretation, but seeking simple acknowledgement that nothing in the verse to this point makes that interpretation impossible.
"for salvation through sanctification" is a dependent clause describing WHAT they have been chosen for. God will save them by making them set apart and ever more Christ-like.
"by the Spirit and faith in the truth." is another dependent clause, this time describing HOW God will accomplish the WHAT of 'salvation through sanctification'. God will employ the Spirit (capitalized indicating the Holy Spirit, third person of the Godhead) and "faith in the truth" to set them apart and save them (and, presumably, 'us').
You have, obviously, viewed the phrase "by the Spirit and faith in the truth" as belonging to "God has chosen" rather than "for salvation through sanctification". My Greek Grammar is no where near up to the task of splitting that hair and any appeal to multiple translations would likely be inconclusive for so important a discussion. So let me address the last phrase with the assumption that "God has chosen by the Spirit and faith in the truth." Nothing in the sentence actually clearly states that the "faith" came from the people. Certainly, the Spirit did not originate with the people, but rather, the Spirit was given by God to the people as the means to accomplish God's choice. It is at least equally possible, if not even probable, that the 'faith' mentioned alongside the Spirit is also from God to accomplish the choice of God. Not to play any sort of 'Scripture pong', but just to demonstrate that there exist other places in scripture that suggest "faith" comes from God, I offer the following (with no suggestion that you should respond to them) ...
- [Rom 12:3 NASB] 3 For through the grace given to me I say to everyone among you not to think more highly of himself than he ought to think; but to think so as to have sound judgment, as God has allotted to each a measure of faith.
- [Eph 2:8 NASB] 8 For by grace you have been saved through faith; and that not of yourselves, [it is] the gift of God;
- [Eph 6:23 NASB] 23 Peace be to the brethren, and love with faith, from God the Father and the Lord Jesus Christ.
It is not unscriptural to suggest that faith is "from God", that faith is a "gift" and that God allots to each "a measure" of faith. In which case, even if "God has chosen by the Spirit and faith in the truth", then there is no reason to doubt that the 'faith' of God's choice was not also "a gift from God" chosen by God in the 'beginning' (Genesis 1:1) and given to those whom God chose in "the measure" that God chose to give it.
Your argument was founded on 2 Thessalonians 2:13 having only one reasonable interpretation, that of Conditional Election. That has been demonstrated to be false; Unconditional Election fits the verse at least as well, if not better, and requires no change to other scriptures to reassign promises of God to Christ rather than those God actually predestined.
