John Calvin Commentary 1 Corinthians 14:4

"He that speaketh in a tongue edifieth himself; but he that prophesieth edifieth the church." — 1 Corinthians 14:4 (ASV)

He that speaks in another tongue edifies himself. In place of what he had said before — that he speaks to God, he now says — he speaks to himself.

But whatever is done in the Church ought to be for the common benefit. Away, then, with that misdirected ambition, which causes the general advantage of the people to be hindered!

Besides, Paul speaks by way of concession, for when ambition makes use of such empty boastings, there is inwardly no desire of doing good; but Paul does, in effect, order away from the common fellowship of believers those men of mere show, who look only to themselves.