He came to be a witness, so that he might testify concerning that Light, so that all people would believe [in Jesus] through him [i.e., through his testimony. See Acts 19:4].
John gave testimony about Jesus, shouting out, ”This person is the one about whom I said, ‘He who will come after me ranks above me because He existed before me.’”
And this is the testimony John [the Immerser] gave when the Jews sent priests and Levites from Jerusalem to ask him, “Who are you?” [Note: Levites were men who assisted the priests in the Temple service].
Paul [then] said, “John immersed people who [demonstrated their] repentance, telling them they must believe in Jesus, the One who would come after him.”
[I was given the responsibility] to enlighten all people regarding the working out of God’s secret plan, which has been kept hidden for ages in [the heart of] God, who created everything.
The Lord is not slow about keeping His promise, like some people are, but is [simply] being patient with you, since He does not want anyone to be destroyed, but He wants everyone to repent [i.e., change their hearts and lives].