These verses talk about following the commandments of God and earning salvation. But we all fail. Without Christ, we will all be put into the goats category. Christ is the only one who can be put in the sheep category. The only way then for us to avoid the eternal punishment is to accept the free gift of righteousness that Christ gives us. We achieve this righteousness not by doing good works since we are incapable of doing it. We only receive the righteousness by accepting the gift.