Augustine, Aquinas, and Calvin all have spoken of inequality as producing unity:
Augustine: Peace between man and man is well-ordered concord. Domestic peace is the well-ordered concord between those of the family who rule and those who obey. Civil peace is a similar concord among the citizens. The peace of the celestial city is the perfectly ordered and harmonious enjoyment of God, and of one another in God. The peace of all things is the tranquility of order. Order is the distribution which allots things equal and unequal, each to its own place. (City of God xix.13)
Aquinas: Equality is the cause of equality in mutual love. Yet between those who are unequal there can be a greater love than between equals; although there be not an equal response: for a father naturally loves his son more than a brother loves his brother; although the son does not love his father as much as he is loved by him. The cause of inequality could be on the part of God; not indeed that He would punish some and reward others, but that He would exalt some above others; so that the beauty of order would the more shine forth among men. Inequality might also arise on the part of nature as above described, without any defect of nature.
Calvin: For the system of proportional right in the Church is this — that while they communicate to each other mutually according to the measure of gifts and of necessity, this mutual contribution produces a befitting symmetry [belle harmonie], though some have more, and some less, and gifts are distributed unequally. (Commentary on 2. Cor. 8:14)