1. Activity - the Spirit Himself does not actually intercede for us: this rather is Paul’s way of expressing that God, by His Spirit, moves us to prayer.
2. Reason - this work takes place in us because our minds are so disturbed by our trials, that we do not know how to frame our thoughts properly; anyway, all prayer, is Spirit-generated prayer, without whose help, we could not pray properly from the heart. “Our thoughts nevertheless continue oppressed with darkness, until the Spirit guides them by His light.”
3. Manner – God, “...by the secret impulse of His Spirit, knocks at our door, and thus opens for himself our hearts,” in order that we might formulate each and every syllable of the proper language of prayer. “He also affects our heart in such a way, that these desires by their fervency penetrate into heaven itself.”
4. Comfort – the fact that we even have this prayer stirred up by God, is a sign of celestial favor already shining forth, if, even though, for a time, our prayers go unanswered.
5. Effect – we are taught by the Spirit how to pray and what to ask for in our prayers.
6. Grace – we thus learn that “these supplies of the Spirit more clearly prove ...that it is by God’s appointment that we strive, by groaning and sighings, for our redemption.”
7. Purpose – we are tempted to complain that the Cross upon our back is too heavy to bear, but “the aid of the Spirit ...is abundantly sufficient to overcome all difficulties. There is no reason for anyone to complain that bearing the cross is beyond their own strength, since we are sustained by a celestial power.”
This, of course, is all part of Paul's wider argument: in spite of all the difficulties that we, as saved saints, face, in this present groaning world, the unbreakable purpose of conforming us to the glorified image of the Son of God, is an absolute certainty. Glory is guaranteed by the sovereign purpose, and predestining, grace of God. A key factor in this pledge is the Spirit's prayer-inciting, prayer-inducing & prayer-directing work.