3:6-10 Thankfulness to God is very imperfect in the present state; but one great end of the ministry of the word is to help faith forward. That which was the instrument to obtain faith, is also the means of increasing and confirming it, namely, the ordinances of God; and as faith cometh by hearing, so it is confirmed by hearing also.
10. Night and day—(See on 1Th 2:9). Night is the season for the saint's holiest meditations and prayers (2Ti 1:3).
praying—connected with, "we joy"; we joy while we pray; or else as Alford, What thanks can we render to God while we pray? The Greek implies a beseeching request.
exceedingly—literally, "more than exceeding abundantly" (compare Eph 3:20).
that which is lacking—Even the Thessalonians had points in which they needed improvement [Bengel], (Lu 17:5). Their doctrinal views as to the nearness of Christ's coming, and as to the state of those who had fallen asleep, and their practice in some points, needed correction (1Th 4:1-9). Paul's method was to begin by commending what was praiseworthy, and then to correct what was amiss; a good pattern to all admonishers of others.