John Gill 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 an unknown tongue
Be it the Hebrew language, or any other; some copies, and the Ethiopic version, read, "with tongues":

edifies himself ;
his heart may be warmed, his affections raised, his devotion kept up, and he be in a very spiritual and comfortable frame, knowing and understanding what he himself says:

but he that prophesies, edifies the church :
which is the great end of the Gospel ministry, which is for the edifying the body of the church: wherefore that which tends to the edification of more, even the whole church, must be preferable to that, which at most can only edify one, and that the speaker himself.