The word 'faith' embraces two ideas: doctrine, as taught of God and received; and subjectively the state of soul. If I have cast off the faith, the doctrine and the state of soul are both gone. Here 'faith' (first time) is the inward energy of grace which holds fast the truth. The two are not separated, but the state of the soul is first in the apostle's mind. In the second, they, having put away a good conscience, did not hold fast the faith, but lost it in some way thus objectively. In this second case, there is the article in Greek, which does not exclude faith in the soul, but leads the mind to the faith. In English 'the faith' would be too absolute or merely doctrinal.