Paul has just referred to the time in the past when he lived by an entirely different principle, and he adds these biographical details as proof that he did not receive his gospel from men but directly from God. Before his conversion he had been a persecutor of the church, a fact that was widely known.
How great is the power of God in conversion that can turn such a bigoted persecutor into the most caring and sacrificial servants of Christ. He describes himself as wasting the church, an intensified form of a verb meaning to ravage. Every true believer has undergone the same complete transformation of character as a result of the new birth.