A.T. Robertson Commentary 1 Corinthians 13:10

"but when that which is perfect is come, that which is in part shall be done away." — 1 Corinthians 13:10 (ASV)

That which is perfect (το τελειον). The perfect, the full-grown (τελος, end), the mature. See on 2:6. Hοταν ελθη is second aorist subjunctive with οταν, temporal clause for indefinite future time.