Jamieson, Fausset and Brown on 1 Timothy 4:9

9. (1Ti 1:15). This verse (Greek), "faithful is the saying, " &c. confirms the assertion as to the "promise" attached to "godliness," 1Ti 4:8, and forms a prefatory introduction to 1Ti 4:10, which is joined to 1Ti 4:9 by "For." So 2Ti 2:11. Godly men seem to suffer loss as to this life: Paul hereby refutes the notion [Bengel]. "God is the Saviour specially of those that believe" (1Ti 4:10), both as to "the life that now is," and also as to "the life which is to come" (1Ti 4:8).