“It is just that the Word of God…, in offering His body as a ransom for us, would discharge our debt by His death. So, united to all mankind by a body like theirs, the incorruptible Son of God can justly clothe all men with incorruptibility.” (De incarn. 9, italics added)
Pretty clear. Salvation is through the death of Christ, totally and completely. No good works to further make one "more" justified are needed. Plenty of good works do naturally follow the true believer though - that is called Sanctification and the fruit of the Spirit (Gal 5:22-23). Just as a real fruit tree produces fruit, so too real believers produce good works, which are the fruit of their salvation.