John 3:11

We speak - Jesus here speaks in the plural number, including himself and those engaged with him in preaching the gospel. Nicodemus had said John 3:2, “we know that thou art,” etc., including himself and those with whom he acted. Jesus in reply said, we, who are engaged in spreading the new doctrines about which you have come to inquire, speak what we know. We do not deliver doctrines which we do not practically understand. This is a positive affirmation of Jesus, which he had a right to make about his new doctrine. he knew its truth, and those who came into his kingdom knew it also. We learn here:

1. That the Pharisees taught doctrines which they did not practically understand. They taught much truth Matthew 23:2, but they were deplorably ignorant of the plainest matters in their practical application.
2. Every minister of the gospel ought to be able to appeal to his own experience, and to say that he knows the truth which he is communicating to others.
3. Every Sunday school teacher should be able to say, “I Know what I am communicating; I have experienced what is meant by the new birth, and the love of God, and the religion which I am teaching.”

Testify - Bear witness to.

That we have seen - Jesus had seen by his omniscient eye all the operations of the Spirit on the hearts of men. His ministers have seen its effects as we see the effects of the wind, and, having seen men changed from sin to holiness, they are qualified to bear witness to the truth and reality of the change. Every successful minister of the gospel thus becomes a witness of the saving power of the gospel.

Ye receive not - Ye Pharisees. Though we give evidence of the truth of the new religion; though miracles are performed, and proof is given that this doctrine came from heaven, yet you reject it.

Our witness - Our testimony. The evidence which is furnished by miracles and by the saving power of the gospel. Men reject revelation though it is attested by the strongest evidence, and though it is constantly producing the most desirable changes in the hearts and lives of men.