Ephesians 6:18

always--Greek, "in every season"; implying opportunity and exigency (Col 4:2). Paul uses the very words of Jesus in Luk 21:36 (a Gospel which he quotes elsewhere, in undesigned consonance with the fact of Luke being his associate in travel, Co1 11:23, &c.; Ti1 5:18). Compare Luk 18:1; Rom 12:12; Th1 5:17. with all--that is, every kind of. prayer--a sacred term for prayer in general. supplication--a common term for a special kind of prayer [HARLESS], an imploring request. "Prayer" for obtaining blessings, "supplication" for averting evils which we fear [GROTIUS]. in the Spirit--to be joined with "praying." It is he in us, as the Spirit of adoption, who prays, and enables us to pray (Rom 8:15, Rom 8:26; Gal 4:6; Jde 1:20). watching--not sleeping (Eph 5:14; Psa 88:13; Mat 26:41). So in the temple a perpetual watch was maintained (compare Anna, Luk 2:37). thereunto--"watching unto" (with a view to) prayer and supplication. with--Greek, "in." Persevering constancy ("perseverance") and (that is, exhibited in) supplication are to be the element in which our watchfulness is to be exercised. for all saints--as none is so perfect as not to need the intercessions of his fellow Christians.

— Jamieson-Fausset-Brown Commentary (public domain)