For ye have heard of my conversation - My conduct, my mode of life, my deportment; see the note at 2 Corinthians 1:12. Probably Paul had himself made them acquainted with the events of his early years. The reason why he refers to this is, to show them that he had not derived his knowledge of the Christian religion from any instruction which he had received in his early years, or any acquaintance which he had formed with the apostles. At first, Paul had been decidedly opposed to the Lord Jesus, and had been converted only by God’s wonderful grace.
In the Jews’ religion - In the belief and practice of Judaism; that is, as it was understood in the time when he was educated. It was not merely in the religion of Moses, but it was in that religion as understood and practiced by the Jews in his time, when opposition to Christianity constituted a very material part of it. In that religion Paul proceeds to show that he had been more distinguished than most persons of his time.
How that beyond measure - In the highest possible degree; beyond all limits or bounds; exceedingly. The phrase which Paul uses here (καθ ̓ ὑπερβολὴν kath' huperbolēn), by hyperbole, is one which he frequently employs to denote anything that is excessive, or that cannot be expressed by ordinary language; see the Greek text in Romans 7:13; 1Co 12:31; 2 Corinthians 1:8; 2Co 4:7, 2 Corinthians 4:17.
I persecuted the church - See Acts 8:3; Acts 9:1 ff.
And wasted it - Destroyed it. The word which is used here, means properly to waste or destroy, as when a city or country is ravaged by an army or by wild beasts. His purpose was utterly to root out and destroy the Christian religion.