We have confidence in the Lord touching you. — Rather, We rely upon you in the Lord: the clause forms the counterpart to the last verse. St. Chrysostom’s whole comment is worth transcription: — “God, saith he, is faithful, and having promised to save, save He assuredly will, but as He promised. And how did He promise? If we would be agreeable, and would hear Him; not unconditionally, nor while we remain inactive like stocks and stones. Yet, well has he added his, ‘We rely in the Lord:’ that is, ‘We trust to His love of men.’ Once more he takes them down, ascribing the whole matter to that quarter; for had he said ‘We trust to you,’ it would have been a great compliment indeed, but would not have taught them to ascribe all to God; and had he said ‘We rely on the Lord that He will keep you,’ without adding ‘upon you,’ and ‘that ye both do and will do what things we command,’ he would have made them less active by casting the whole upon the power of God.” (See the passage of Galatians referred to in the margin.)
Both do and will do. — The emphasis of the sentence is on the future tense, the commendation of the present being only intended to do away the rebuke which might have been conveyed by the future alone. How careful St. Paul is not to wound susceptibilities, though he never “pleases men”! (See, for instance, Notes on 1 Thessalonians 4:1; 1 Thessalonians 4:9-10; 1 Thessalonians 5:11.) This expression of confidence is a happy rhetorical means of preparing readers for the commands which are to follow.