2 Thessalonians 2:15

Hence, then, brethren, stand firm, and hold fast the instructions which ye were taught - whether through discourse, or through our letter.

1 Corinthians 11:2

Now I praise you, that, in all things, ye have me in remembrance, and, even as I delivered unto you the instructions, ye hold them fast.

1 Corinthians 16:13

Be on the watch, stand firm in the faith, be men - be strong;

2 Thessalonians 2:2

That ye be not quickly tossed from your mind, nor be put in alarm - either by spirit, or by discourse, or by letter as by us, as that the day of the Lord, hath set in:

2 Thessalonians 3:6

Howbeit, we charge you, brethren, - that, in the name of the Lord Jesus Christ, ye be withdrawing yourselves from every brother - who, in a disorderly way, doth walk, and not according to the instruction which ye received from us.

Romans 16:17

But I beseech you, brethren, to keep an eye upon them who are causing divisions and occasions of stumbling, aside from the teaching which, ye, have learned, - and be turning away from them;

1 Corinthians 15:58

So, then, my beloved brethren, - become ye, steadfast, immovable, superabounding in the work of the Lord, at all times; knowing that, your toil, is not in vain in the Lord.

Philippians 4:1

So then, my brethren, beloved and longed for, my joy and crown, - thus, stand fast in the Lord, beloved.

2 Thessalonians 3:14

And, if anyone be not giving ear unto our word through means of this letter, on this one, set a mark - not to be mixing yourselves up with him, - that he may be reproved;

Jude 1:3

Beloved! though I was using all diligence to be writing unto you concerning our common salvation, yet have I had necessity to write at once unto you, exhorting you to be earnestly contending for, the faith, once for all delivered unto the saints.

Treasury of Scripture Knowledge

Summary

Therefore, brethren, stand fast, and hold the traditions which ye have been taught, whether by word, or our epistle.

Bible References

Whether

2 Thessalonians 2:2
That ye be not quickly tossed from your mind, nor be put in alarm - either by spirit, or by discourse, or by letter as by us, as that the day of the Lord, hath set in:
2 Thessalonians 3:14
And, if anyone be not giving ear unto our word through means of this letter, on this one, set a mark - not to be mixing yourselves up with him, - that he may be reproved;