NET
12 Compete well for the faith and lay hold of that eternal life you were called for and made your good confession for in the presence of many witnesses.
Darby
12 Strive earnestly [in] the good conflict of faith. Lay hold of eternal life, to which thou hast been called, and hast confessed the good confession before many witnesses.
KJV
12 Fight the good fight of faith, lay hold on eternal life, whereunto thou art also called, and hast professed a good profession before many witnesses.