Shared ground
Paul contrasts two kinds of “training.” Physical exercise is acknowledged as genuinely beneficial, but limited in scope and duration (v.8). “Godliness” is presented as broadly useful (“for all things”) because it is tied to a promise that reaches into both “the life which is now” and “that which is to come” (v.8). Verse 9 pauses to underline that this is not a throwaway idea: it is a dependable statement meant to be fully received.
Paul then grounds the claim in experience: he and his coworkers keep laboring and endure public criticism “to this end” because their hope is set on “the living God” (v.10). The logic is that the effort makes sense if God is real, living, and able to deliver what he promises.
Where interpretation differs
Two phrases invite different readings while staying close to Paul’s main point.
First, “promise of the life which is now.” Some take this to mean godliness normally brings recognizable benefits in ordinary life (e.g., relational stability, wisdom, endurance, a community’s trust), though not a guarantee of comfort. Others read it more narrowly as the experience of spiritual life in the present (life with God now), without implying improved circumstances.
Second, “Savior of all men, especially of those who believe” (v.10). Some understand “Savior of all” as meaning God in some sense provides saving help broadly (for example, preserving life, showing mercy, offering salvation), while believers receive a fuller or final experience of that salvation (“especially”). Others read “Savior of all” as emphasizing God’s saving posture toward all people (no ethnic or social limitation) while “especially believers” specifies who actually receives salvation in the saving sense.
Why the disagreement exists
Paul uses short, compressed phrases without spelling out details. “Life now” could refer to everyday life benefits, present spiritual life, or both (an interpretive pressure point noted in Stage A). Likewise, “Savior of all…especially believers” can be heard as two levels of help (general and special) or as a broad statement qualified by a specific one.
What this passage clearly contributes
Explicitly, the text claims: bodily exercise has some value but limited value; godliness is valuable in every direction because it carries promise for present and future life; this claim is reliable and meant to be accepted; Paul’s ministry endurance is fueled by hope in the living God (vv.8–10). Theologically inferred from these claims, Paul treats godliness as worth sustained effort because its payoff is not confined to one domain or one time horizon, and because the God hoped in is characterized as a saving God (v.10; compare 1 Timothy 4:8).