'Testifying' in the Bible

But when Silas and Timothy came down from Macedonia, Paul began devoting himself completely to the word, solemnly testifying to the Jews that Jesus was the Christ.

solemnly testifying to both Jews and Greeks of repentance toward God and faith in our Lord Jesus Christ.

So, having obtained help from God, I stand to this day testifying both to small and great, stating nothing but what the Prophets and Moses said was going to take place;

When they had set a day for Paul, they came to him at his lodging in large numbers; and he was explaining to them by solemnly testifying about the kingdom of God and trying to persuade them concerning Jesus, from both the Law of Moses and from the Prophets, from morning until evening.