Charles Hodge, in his exposition on 1 & 2 Corinthians:
Every organism, or organic whole, supposes diversity and unity. That is, different parts united so as to constitute one whole. The apostle had taught that in the unity of the church there is a diversity of gifts. This is illustrated by a reference to the human body. It is one, yet it consists of many members. And this diversity is essential to unity; for unless the body consisted of many members, it would not be a body, i.e. an organic whole.
Charles Colsonin The Body:
Diversity within the Body, while it may chafe and bind and even pain, provides a healthy corrective ... The fact is, we can learn from one another ... Respecting and appreciating different traditions not only teaches us more about our faith, but encourages a measure of theological humility. This attitude helps us avoid the kind of rigid conformity that says everyone must look, act, talk and think alike. And this also helps us make the gospel accessible to all people.
Marlene Nathan on 1 Co 12.12-30:
The very thing that Paul says here will create our unity is now a source of division and disunity: the Holy Spirit. Christians are more divided over the person and work of the Holy Spirit than almost anything else. When we reject the means for unity that God has provided, then we are forced to substitute man-made alternatives (external standards and conformity to rules) in order to be united.