(7) For we brought nothing into this world, and it is certain we can carry nothing out.

 1 Timothy 6:3-8

(3) If any man teach otherwise, and consent not to wholesome words, even the words of our Lord Jesus Christ, and to the doctrine which is according to godliness; (4) He is proud, knowing nothing, but doting about questions and strifes of words, whereof cometh envy, strife, railings, evil surmisings, (5) Perverse disputings of men of corrupt minds, and destitute of the truth, supposing that gain is godliness: from such withdraw thyself. (6) But godliness with contentment is great gain. (7) For we brought nothing into this world, and it is certain we can carry nothing out. (8) And having food and raiment let us be therewith content.
King James Version   Change Bible versions

The way this argument progresses is intriguing. He starts by mentioning those who were apostatizing, preaching a false gospel, and rejecting what Christ had given the church inthe gospel, yet he ends up speaking about contentment.

His thought is this: Those who argue against the doctrines of God and against the church are essentially discontent. They are at the initial stages of presumptuousness, or they may have already become fully presumptuous. They try to use their "godliness" to get some sort of advantage or gain for themselves. The motives on the surface may seem to be that they are trying to be godly, but underneath, the real motive is to get something for themselves.

We should not think of this "gain" as only money or goods. It could be respect, or favor with somebody. It could be notoriety or having people think that one is smart. It could be having authority of some kind - ordination or having a group of followers. It could be many things. What it comes down to is presumptuousness, because the person who does these things is reaching beyond his place.

God put the person in the body at a specific point, to do a certain a job, and when he starts doing the types of things that Paul mentions - arguing against the doctrine, for instance - he is taking a job that he has not been given. Paul says the real gain comes when we behave in a godly manner and reckon that what we have is sufficient for us.

— Richard T. Ritenbaugh