18. always--Greek, "in every season"; implying opportunity and exigency (Col 4:2). Paul uses the very words of Jesus in Lu 21:36 (a Gospel which he quotes elsewhere, in undesigned consonance with the fact of Luke being his associate in travel, 1Co 11:23, &c.; 1Ti 5:18). Compare Lu 18:1; Ro 12:12; 1Th 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 (Ro 8:15, 26; Ga 4:6; Jude 20).
      watching--not sleeping (Eph 5:14; Ps 88:13; Mt 26:41). So in the temple a perpetual watch was maintained (compare Anna, Lu 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.

JFB.