this system of things: Or “this age.”​—See study note on 1Co 1:20.

God’s wisdom in a sacred secret: That is, the wise arrangement that God put in place for ending the rebellion that started in Eden and for bringing about universal peace and unity. (See Glossary, “Sacred secret.”) The declaration of the “sacred secret” (Greek, my·steʹri·on; see study note on Mt 13:11) began with Jehovah’s prophecy at Ge 3:15. Jehovah’s “sacred secret” centers on Jesus Christ. (Eph 1:9, 10; Col 2:2) It includes Jesus’ identity as the promised offspring, or Messiah, and his role in God’s Kingdom (Mt 13:11); the selection of anointed ones​—taken from among both Jews and Gentiles​—to be Christ’s joint heirs, with whom he shares the Kingdom (Lu 22:29, 30; Ro 11:25; Eph 3:3-6; Col 1:26, 27); and the unique nature of this congregation composed of 144,000 “bought from among mankind as firstfruits to God and to the Lamb” (Re 14:1, 4). These facets can be understood only by those who thoroughly study the Scriptures.

the hidden wisdom: Paul called the sacred secret “the hidden wisdom,” that is, hidden from “the rulers of this system of things.” (1Co 2:8) God through his spirit reveals this secret to his Christian servants so that they might make it public.

the systems of things: The Greek word used here, ai·onʹ, has the basic meaning “age.” It can refer to a state of affairs or to features that distinguish a certain period of time. In this context, the term refers to those systems that have developed during man’s history since the rebellion in Eden.​—See Glossary, “System(s) of things,” and study note on 1Co 10:11.

executed: Or “executed (fastened) on a stake.”​—See study note on Mt 20:19 and Glossary, “Stake”; “Torture stake.”

Eye has not seen and ear has not heard: The quotation in this verse is not found in the Hebrew Scriptures exactly as Paul words it. He seems to be combining the thoughts of Isa 52:15 and 64:4. Neither Paul nor Isaiah was referring to the future blessings that Jehovah has prepared for his people. Rather, Paul here applies Isaiah’s words to the blessings that first-century Christians were already enjoying, including their spiritual enlightenment and understanding of “the deep things of God.” (1Co 2:10) People who lack spirituality do not value such blessings. Their eye cannot see, or discern, spiritual truths, and their ear cannot hear, or understand, such things. Knowledge of “the things that God has prepared for those who love him” does not even enter into the hearts of such people. But God has revealed these precious truths through his spirit to men and women who, like Paul, are dedicated to Him.

the spirit of the world: Paul here refers to the dominant attitudes and inclinations of the world of humankind alienated from Jehovah God. Because of the pervasive influence of Satan, the spirit of the world is marked by selfishness, immorality, and disrespect for Jehovah and his righteous standards. (Eph 2:1-3; 1Jo 5:19) The spirit of the world works in direct opposition to the spirit that is from God, his holy spirit.​—For a discussion of the term “spirit” as used in the Bible, see Glossary, “Spirit.”

a physical man: In this context, the term “physical man” does not refer merely to a human of flesh and blood. The expression is used in contrast with “the spiritual man” in verse 15, so it refers to a person who has no interest in or appreciation for spiritual matters. The Greek word for “physical” used here, psy·khi·kosʹ, is derived from the word psy·kheʹ, sometimes rendered “soul” in this translation. As used in the Bible, psy·kheʹ generally refers to that which is physical, tangible, visible, and mortal. (See Glossary, “Soul.”) So “a physical man” is one who is preoccupied with the desires that are associated with the physical or material life to the exclusion of spiritual things.​—See study note on 1Co 2:15.

the spiritual man: Lit., “the spiritual (one).” Paul here contrasts the spiritual man with the “physical man” mentioned in the preceding verse. (See study note on 1Co 2:14.) A spiritual person values spiritual matters and is guided by God’s spirit. God is very real to spiritually-minded people, and they strive to “become imitators of God.” (Eph 5:1) They endeavor to obtain God’s view of matters and meet his standards for living. The spiritual person examines, or clearly sees, the wrong course of the physical man.

who has come to know the mind of Jehovah . . . ?: The answer to this rhetorical question is: “No one, of course.” (Compare Ro 11:33, 34, where Paul quotes from the same scripture, Isa 40:13.) Paul then says: “But we do have the mind of Christ.” Humans can never fully understand all of Jehovah’s thoughts. Christians can, however, come to know God better by studying “the mind of Christ” and cultivating his way of thinking because Christ is “the image of the invisible God.” (Col 1:15; see study note on we do have the mind of Christ in this verse.) In fact, the better a Christian understands Christ’s mind, the better he will understand God’s mind.

the mind of Jehovah: Paul is here quoting from Isa 40:13, where the Hebrew text reads “the spirit of Jehovah.” However, Paul was apparently quoting from the Septuagint, which uses “mind” (Greek, nous) instead of “spirit.” Although available manuscripts of both the Septuagint and the Christian Greek Scriptures read “mind of Lord,” there are solid reasons for believing that the divine name was used in corresponding manuscripts that existed in the first century C.E.​—See App. A5, C1, and C2.

Jehovah: In this quote from Isa 40:13, the divine name, represented by four Hebrew consonants (transliterated YHWH), occurs in the original Hebrew text of Isaiah.​—See App. C1 and C2.

we do have the mind of Christ: A Christian can have “the mind of Christ” by coming to know the pattern of Jesus’ thinking. Such a person meditates on all aspects of Christ’s personality and then adopts Christ’s way of thinking and imitates his example of humility and obedience. (1Pe 2:21) A Christian’s “dominant mental attitude” will then reflect the thinking of Christ, whose “mind” reflects the thinking of Jehovah.​—Eph 4:23; Joh 14:9.