Parallel
John 1:7
Nestle 1904 Greek New Testament · Berean Standard Bible
οὗτος ἦλθεν εἰς μαρτυρίαν ἵνα μαρτυρήσῃ περὶ τοῦ φωτός ἵνα πάντες πιστεύσωσιν δι’ αὐτοῦ
He came as a witness to testify about the Light, so that through him everyone might believe.