The triune God of the Bible testifies about the truth that Jesus Christ is the Son of God. The terms for testify or testimony are found 9 times in these verses. John’s purpose is that we believe this true testimony about salvation in Christ. When John mentions “the water and the blood” as two that testify, he refers to Jesus’ Incarnation as shown from His baptism to His crucifixion. Because God has testified about the truth, failure to believe God amounts to making Him a liar. This horrible sin will keep us from eternal life if we were to persist in it. God, however, provided the perfect, once for all sacrifice through Christ’s blood. The great new covenant promise is that God will remember our sins no more.

Sermon handout, slides and reference available under Downloads tab. The textual issue that Bob DeWaay mentioned can be read in the attachment titled Excursus: Johannine Comma.