They only heard the report: "The man who formerly persecuted us is now preaching the faith he once tried to destroy." (NIV)
They were only hearing it said, He who used to persecute us is now proclaiming the very faith he once reviled and which he set out to ruin and tried with all his might to destroy. (AMP)
But they had heard only, That he which persecuted us in times past now preacheth the faith which once he destroyed. (KJV)