Commentaries
3:20,21 It is proper always to end prayers with praises. Let us expect more, and ask for more, encouraged by what Christ has already done for our souls, being assured that the conversion of sinners, and the comfort of believers, will be to his glory, for ever and ever.
20. unto him—contrasted with ourselves and our needs. Translate, "that is able above all things (what is above all things) to do exceeding abundantly above what we ask or (even) think": thought takes a wider range than prayers. The word, above, occurs thrice as often in Paul's writings, as in all the rest of the New Testament, showing the warm exuberance of Paul's spirit.
according to the power—the indwelling Spirit (Ro 8:26). He appeals to their and his experience.