One of the most interesting claims is need for equality in society. I’ve rarely seen any attempt to defend what kind of equality is needed. There are many senses of equality and many of them are equivocal.
“All men are equal” is a proposition as ambiguous as it is invoked. It is manifest that all men are not equal in many ways, some trivial and others of eminent importance. All men are not equal in magnitude, which is the principle meaning of “equality.” Not all men are the same size, height or shape. All men are not equal in virtue is of great importance. I trust an honest man, but not a liar, but these are differences in virtue. I call a mechanic and not a mathematician to fix my car. This is a matter of an inequality of virtue, though not moral virtue. There is then very good reason to discriminate and it would be manifestly unjust to treat all men as equal in every way.
The principle meaning of “All men are equal” in the Christian sense fundamentally stems from “All men are sinners.” This does not mean that all men have sinned, though we all have. We are not labeled with the scarlet letter of “sinner” because we sin, but we sin because we are sinners. Even the most virtuous man is a sinner, because the nature of Original Sin cuts down to the bottom. We are profoundly wounded and our will no longer seeks the good but tends toward evil. Even St. Therese recognized that if she did not sin it was not because she was better but because God had forgiven her sins in advance. From this equality of sinners comes then the equality in Christ. Christ came to save all sinners and all men are sinner. So, we are all equally dignified by the great gift of Christ’s redemption and the glory that is offered to us freely.
Even more fundamental than that all men are sinners is that all men are created in the image and likeness of God. It is in virtue of this that we can and do fall short and sin. In Christ, this image is restored from sin and exalted to the adopted sons of God.