The rich man asked our Lord, "What must I do to gain eternal life?" The problem with this question is twofold. First, he underestimates the state of man after the fall: Without God's grace, there is nothing we can possibly to to attain salvation. Second, he takes too narrow and legalistic a read of the Commandments - he does not understand that to "not kill" means not only not to murder but not even to have anger towards our neighbor, etc.
However, by God's grace, all is possible - even eternal life! Furthermore, Our Lord tells St Peter that any sacrifice we make for God is really no sacrifice at all, since we receive an hundredfold in this life, and eternal salvation in the life to come.
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