Is Christ our Master?

Although the title "Master" is only given to Christ twice in Paul's epistles (Eph. 6:9; Col. 4:1), it is not unscriptural for us to regard Christ as our master for a few reasons: (1) we are servants of God, as well as sons, in the sense that we are called to do his will (Rom. 6:22; 12:1, 11); and (2) Master is very similar in sense to "Lord" (cf. Mt. 10:24; John 13:13-14).

In both passages where Paul uses "Master" as a title for Christ, he is reminding earthly masters that they are under authority to a heavenly Master, the Lord Christ (Col. 3:24).  It's not only Christian masters, however, that have Christ as Master, but rather all saints.  I think that this title may not be used as much since the title "Lord" magnifies Christ's Deity more. 

But it's perfectly fine for a believer to refer to the Lord this way, even in a devotional sense.  "Master" was Frances Ridley Havergal's favourite title for Christ, and you can find this title in her hymns ("Master, speak! Thy servant heareth") and writings (Kept for the Master's Use). This reminded me of another use of "master" in reference to Christ, though not as a title, in 2 Timothy 2:21, "If a man therefore purge himself from these, he shall be a vessel unto honour, sanctified, and meet for the master's use, and prepared unto every good work."  What a blessing to be under this Master and not the cruel ones that preceded him (Acts 26:18; Rom. 6:17; Eph. 2:2)!