The same came for a witness, to bear witness of the Light, that all [men] through him might believe.
Berean Study Bible (BSB) - John 1:7 >He came as a witness to testify about the Light, so that through him everyone might believe.
Textus Receptus (TR) - John 1:7 >Οὗτος ἦλθεν εἰς μαρτυρίαν, ἵνα μαρτυρήσῃ περὶ τοῦ φωτός, ἵνα πάντες πιστεύσωσι δι᾿ αὐτοῦ.