romans 8:26 Likewise the Spirit also helpeth our infirmities: for we know not what we should pray for as we ought: but the Spirit itself maketh intercession for us with groanings which cannot be uttered. - Free Bible Online

      26, 27. Likewise the Spirit also, &c.--or, "But after the like manner doth the Spirit also help.
      our infirmities--rather (according to the true reading), "our infirmity"; not merely the one infirmity here specified, but the general weakness of the spiritual life in its present state, of which one example is here given.
      for we know not what we should pray for as we ought--It is not the proper matter of prayer that believers are at so much loss about, for the fullest directions are given them on this head: but to ask for the right things "as they ought" is the difficulty. This arises partly from the dimness of our spiritual vision in the present veiled state, while we have to "walk by faith, not by sight" (see on 1Co 13:9 and 2Co 5:7), and the large admixture of the ideas and feelings which spring from the fleeting objects of sense that there is in the very best views and affections of our renewed nature; partly also from the necessary imperfection of all human language as a vehicle for expressing the subtle spiritual feelings of the heart. In these circumstances, how can it be but that much uncertainty should surround all our spiritual exercises, and that in our nearest approaches and in the freest outpourings of our hearts to our Father in heaven, doubts should spring up within us whether our frame of mind in such exercises is altogether befitting and well pleasing to God? Nor do these anxieties subside, but rather deepen, with the depth and ripeness of our spiritual experience.
      but the Spirit itself--rather, "Himself." (See end of Ro 8:27).
      maketh intercession for us with groanings which cannot be uttered--that is, which cannot be expressed in articulate language. Sublime and affecting ideas, for which we are indebted to this passage alone! "As we struggle to express in articulate language the desires of our hearts and find that our deepest emotions are the most inexpressible, we 'groan' under this felt inability. But not in vain are these groanings. For 'the Spirit Himself' is in them, giving to the emotions which He Himself has kindled the only language of which they are capable; so that though on our part they are the fruit of impotence to utter what we feel, they are at the same time the intercession of the Spirit Himself in our behalf."

JFB.