Note 4 at 1Co 2:15: This "spiritual" person that Paul was speaking of is the opposite of the "natural" person he spoke of in the previous verse (see note 1 at 1Co 2:14). This is describing people who are not governed by their own natural, human powers but are filled with and governed by the Spirit of God.

Note 5 at 1Co 2:15: The English word "judge" can mean a variety of different things (see note 46 at Mt 7:1). In this instance, it means to "scrutinize" or "determine" (Strong's Concordance).

Paul was stating that a spiritual person (see note 4 at this verse) is someone who is operating with the wisdom of God and is therefore qualified to discern people and situations correctly.

1Co 2:16 tells us why that is so. It is because no one understands the way God thinks except for the Holy Spirit and those whom the Holy Spirit teaches. This is the same thing that 1Co 2:11 says.

Therefore, no unspiritual person is able to judge a person ruled by the Spirit of God.