You misunderstand what "traditions" therein refer to:
Instruction was passed by mouth and written word (hence "letter", "epistle"):
2Th 2:2 That ye be not soon shaken in mind, or be troubled, neither by spirit, nor by word, nor by letter as from us, as that the day of Christ is at hand.
2Th 2:15 Therefore, brethren, stand fast, and hold the traditions which ye have been taught, whether by word, or our epistle.
Paul stated that all things needed to be proved by the word of God:
1Th 5:21 Prove all things; hold fast that which is good.
1Co 14:32 And the spirits of the prophets are subject to the prophets.
2Ti 3:14 But continue thou in the things which thou hast learned and hast been assured of, knowing of whom thou hast learned them;
2Ti 3:15 And that from a child thou hast known the holy scriptures, which are able to make thee wise unto salvation through faith which is in Christ Jesus.
2Ti 3:16 All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:
2Ti 3:17 That the man of God may be perfect, throughly furnished unto all good works.
Jesus himself, and Paul and Peter warned of false "traditions" that were already in circulation in their day.
Col_2:8 Beware lest any man spoil you through philosophy and vain deceit, after the tradition of men, after the rudiments of the world, and not after Christ.
2Pe_3:17 Ye therefore, beloved, seeing ye know these things before, beware lest ye also, being led away with the error of the wicked, fall from your own stedfastness.
Others were already corrupting the word:
2Co_2:17 For we are not as many, which corrupt the word of God: but as of sincerity, but as of God, in the sight of God speak we in Christ.
The question is what "traditions" was Paul referring to in context? Made up stuff with no other foundation than devils and men?
2Th 2:15 Therefore, brethren, stand fast, and hold the traditions which ye have been taught, whether by word, or our epistle.
Notice, that in
2 Thessalonians 2:2, this is referred to before:
2Th 2:2 That ye be not soon shaken in mind, or be troubled, neither by spirit, nor by word, nor by letter as from us, as that the day of Christ is at hand.
Paul already told them in 1 Thessalonians, and it was in regards the second coming (see context) and what they (Thessalonians) were to be doing unto the coming of Jesus.
So Paul himself, actually referred to his personal face to face speaking, and also written in an earlier "our epistle". (1 Thess.)
In
1 Thessalonians 1:3, we see that Paul commended them for their "work of faith and labour of love".
In
1 Thessalonians 1:5 (2:2-5) it speaks of the "gospel" did not come in "word" ("speak", "exhortation", "words") only, but in "power" (Holy Spirit).
In
1 Thessalonians 2:8 it speaks of the "gospel" having been "imparted".
In
1 Thessalonians 2:9 it speaks of the "gospel" having been "preached" and also of the "labour and travail".
1Th 2:10 Ye are witnesses, and God also, how holily and justly and unblameably we behaved ourselves among you that believe:
1Th 2:11 As ye know how we exhorted and comforted and charged every one of you, as a father doth his children,
1Th 2:12 That ye would walk worthy of God, who hath called you unto his kingdom and glory.
1Th 2:13 For this cause also thank we God without ceasing, because, when ye received the word of God which ye heard of us, ye received it not as the word of men, but as it is in truth, the word of God, which effectually worketh also in you that believe.
And so Paul continues by speaking of his example of labour (not in laziness, indolence as some were, being busybodies, etc) among them, and in the gospel:
1Th 4:1 Furthermore then we beseech you, brethren, and exhort you by the Lord Jesus, that as ye have received of us how ye ought to walk and to please God, so ye would abound more and more.
Herein is then the "tradition" which Paul spake of that was spoken unto them:
1Th 4:2 For ye know what commandments we gave you by the Lord Jesus.
1Th 4:3 For this is the will of God, even your sanctification, that ye should abstain from fornication:
1Th 4:4 That every one of you should know how to possess his vessel in sanctification and honour;
1Th 4:5 Not in the lust of concupiscence, even as the Gentiles which know not God:
1Th 4:6 That no man go beyond and defraud his brother in any matter: because that the Lord is the avenger of all such, as we also have forewarned you and testified.
1Th 4:7 For God hath not called us unto uncleanness, but unto holiness.
1Th 4:8 He therefore that despiseth, despiseth not man, but God, who hath also given unto us his holy Spirit.
1Th 4:9 But as touching brotherly love ye need not that I write unto you: for ye yourselves are taught of God to love one another.
1Th 4:10 And indeed ye do it toward all the brethren which are in all Macedonia: but we beseech you, brethren, that ye increase more and more;
1Th 4:11 And that ye study to be quiet, and to do your own business, and to work with your own hands, as we commanded you;
1Th 4:12 That ye may walk honestly toward them that are without, and that ye may have lack of nothing.
The Coming of the Lord
1Th 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.
1Th 4:14 For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with him.
1Th 4:15 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.
1Th 4:16 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:
1Th 4:17 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.
1Th 4:18 Wherefore comfort one another with these words.
And more:
1Th 5:12 And we beseech you, brethren, to know them which labour among you, and are over you in the Lord, and admonish you;
1Th 5:13 And to esteem them very highly in love for their work's sake. And be at peace among yourselves.
1Th 5:14 Now we exhort you, brethren, warn them that are unruly, comfort the feebleminded, support the weak, be patient toward all men.
1Th 5:15 See that none render evil for evil unto any man; but ever follow that which is good, both among yourselves, and to all men.
1Th 5:16 Rejoice evermore.
1Th 5:17 Pray without ceasing.
1Th 5:18 In every thing give thanks: for this is the will of God in Christ Jesus concerning you.
1Th 5:19 Quench not the Spirit.
1Th 5:20 Despise not prophesyings.
1Th 5:21 Prove all things; hold fast that which is good.
1Th 5:22 Abstain from all appearance of evil.
1Th 5:23 And the very God of peace sanctify you wholly; and I pray God your whole spirit and soul and body be preserved blameless unto the coming of our Lord Jesus Christ.
1Th 5:24 Faithful is he that calleth you, who also will do it.
1Th 5:25 Brethren, pray for us.
1Th 5:26 Greet all the brethren with an holy kiss.
1Th 5:27 I charge you by the Lord that this epistle be read unto all the holy brethren.
1Th 5:28 The grace of our Lord Jesus Christ be with you. Amen.
Ain't that sumthin'.
Paul wasn't referring to man-made 'tradition' that came along later and passed itself off as truth.
