1 Corinthians 2:10, and the surrounding verses, give believers reason to claim that the natural (or unsaved) person will not understand the deep things of God. As such, we should not be surprised that Christians and non-Christians disagree about these things. But what about Christians disagreeing with other Christians? Does this biblical passage actually teach that those who do not understand the deep things of God are not being spiritual? If that is the case, one could argue that anyone who disagrees with me about “deep” doctrine is in fact being unspiritual (so long as I truly believe that my doctrine is correct). Surely that is not right.
First, contextually, verse 16 states that “we [Christians] have the mind of Christ.” Since believers possess that mind and yet still disagree, it cannot be the case that mere disagreement over these issues indicates a worldly attitude. Instead, the passage seems to be teaching within the context of salvation (and the power of God). In these cases, Christians must be united. The very Gospel is at stake, and one who does not believe the Gospel is not saved. So, within the context of the Gospel, if someone disagrees, then yes—they do not have the Spirit of God within them. However, outside of this context, the Lord allows us free will (in my opinion, this free will with respect to at least some of our doxastic functions indicates a correlation between rationality and free will. However, even if it turns out none of our non-Gospel doxastic functions are voluntary the case above is still intact. After all, how can one be punished or decried for something he could not very well help, change, or influence causally?)
The point is that Christians should be very charitable toward one another in areas of non-Gospel doctrine. This does not mean that everyone is correct, or we cannot have doctrinal disputes and debate. We can, and should, have those discussions—within reason (here’s looking at Calvinism-Arminianism-Molinism-Augustinianism-Whateverism). But in all things, let there be charity (1 Cor. 16:14).