To Titus, mine own son after the common faith
Not in a natural, but in a spiritual sense; the apostle being the instrument of his conversion, as he was of the conversion of Onesimus, and of many of the Corinthians, and therefore is said to beget them, ( Philemon 1:10 ) ( 1 Corinthians 4:15 ) and so was their spiritual father, and they his children: Titus was, in this sense, his "own son", or a true son, a legitimate one; a true convert; one really born again; a sincere believer, an Israelite indeed: and this he was "after the common faith"; either the doctrine of faith, which is but one, and is common to all the saints; or the grace of faith, which though different in degrees, yet is alike precious faith in all; the same for nature, kind, object, operation, and effects: and this phrase is used to show in what sense Titus was son to the apostle; as he was a believer, and no otherwise.
Grace, mercy, and peace
which is the apostle's usual salutation; see ( 1 Timothy 1:2 ) . The word "mercy" is left out in the Claromontane copy, and in the Vulgate Latin, Syriac, and Ethiopic versions.