15. Therefore--because they are so washed white; for without it they could never have entered God's holy heaven; Re 22:14, "Blessed are those who wash their robes (the oldest manuscripts reading), that they may have right to the tree of life, and may enter in through the gates into the city"; Re 21:27; Eph 5:26, 27.
      before--Greek, "in the presence of." Mt 5:8; 1Co 13:12, "face to face."
      throne . . . temple--These are connected because we can approach the heavenly King only through priestly mediation; therefore, Christ is at once King and Priest on His throne.
      day and night--that is, perpetually; as those approved of as priests by the Sanhedrim were clothed in white, and kept by turns a perpetual watch in the temple at Jerusalem; compare as to the singers, 1Ch 9:33, "day and night"; Ps 134:1. Strictly "there is no night" in the heavenly sanctuary (Re 22:5).
      in his temple--in what is the heavenly analogue to His temple on earth, for strictly there is "no temple therein" (Re 21:22), "God and the Lamb are the temple" filling the whole, so that there is no distinction of sacred and secular places; the city is the temple, and the temple the city. Compare Re 4:8, "the four living creatures rest not day and night, saying, Holy," &c.
      shall dwell among them--rather (Greek, "scenosei ep' autous"), "shall be the tabernacle over them" (compare Re 21:3; Le 26:11, especially Isa 4:5, 6; 8:14; 25:4; Eze 37:27). His dwelling among them is to be understood as a secondary truth, besides what is expressed, namely, His being their covert. When once He tabernacled among us as the Word made flesh, He was in great lowliness; then He shall be in great glory.

JFB.