NET
5 They know, because they have known me from time past, if they are willing to testify, that according to the strictest party of our religion, I lived as a Pharisee.
Darby
5 who knew me before from the outset [of my life], if they would bear witness, that according to the strictest sect of our religion I lived a Pharisee.
KJV
5 Which knew me from the beginning, if they would testify, that after the most straitest sect of our religion I lived a Pharisee.