20Now to Him who is able to do exceeding abundantly beyond all that we ask or think, according to the power that works within us, 21to Him be the glory in the church and in Christ Jesus to all generations forever and ever. Amen.
Eph_3:20 "to Him who is able" This begins one of Paul's marvelous doxologies which closes the doctrinal section of this circular letter. This is a wonderful title for God used three times in the NT (cf. Rom_16:25; Jud_1:24). Each of these texts deal with different aspects of God's activities.
This is a characteristic Pauline compound superlative meaning, "exceeding, abundantly more" (cf. 1Th_3:10; 1Th_5:13). See Special Topic: Paul's Use of Huper Compounds at Eph_1:19. It is bad grammar, but great theology!
▣ "according to the power that works within us," This is a reference to the indwelling Christ through the Spirit (cf. Eph_3:7; Eph_3:16-17; Gal_2:20; Col_1:27). This permanent indwelling Spirit in each and every believer is the difference between the Old Covenant and the New, i.e. "new heart," "new mind," "new spirit" (cf. Eze_36:26-27).
Eph_3:21 "be the glory in the church and in Christ Jesus" Here is the exalted place of Jesus' Bride and Body, the Church (cf. Eph_1:23), His blood-bought, Spirit-filled people! The term "church" is from two Greek terms, "out of" and "to call." It was used in Greco-Roman culture for town meetings (cf. Act_19:32). In Jewish life this term was used to translate the significant theological concepts of "the assembly of Israel" or qahal (cf. Exo_12:6; Exo_16:3; Lev_4:13; Num_14:5; Num_20:6; Deu_5:22; Deu_9:10; Deu_10:4; Deu_18:16). The early believers saw themselves as the true and ongoing "People of God" (cf. Gal_6:16; 1Pe_2:5-9; Rev_1:6).