But God hath revealed them unto us by his Spirit: for the Spirit searcheth all things, yea, the deep things of God.
Revealed ... by ... Spirit. Inspiration of thoughts (so far as truth essential to salvation is concerned) makes the Christian (1 Corinthians 3:16; 1 Corinthians 12:3; Matthew 16:17; John 16:13; 1 John 2:20; 1 John 2:27); that of words, the PROPHET (1 Corinthians 2:13; 2 Samuel 23:1-2; 1 Kings 13:1; 1 Kings 13:5; 2 Peter 1:21). The secrets of revelation remain secret, not because God will not reveal them (for the very notion of revelation implies an unveiling of what was veiled), but because natural men have not the will or power to comprehend them. The Spirit-taught alone know these secrets (Psalms 25:14; John 7:17; John 15:15).
Unto us - the "perfect" believers (1 Corinthians 2:6). Intelligent men may understand the outline of doctrines; but without the Holy Spirit's revelation these will be to them a mere skeleton, correct, but wanting life (Luke 10:21).
The Spirit searcheth - working in us and with our spirits (cf. Romans 8:16; Romans 8:26-27). The Old Testament shows us God (the Father) for us; the gospels, God (the Son) with us; the Acts and letters, God (the Holy Spirit) in us (1 Corinthians 3:16).
Deep things of God (Psalms 92:5) - His divine Being, attributes, and counsels. The Spirit delights to explore the infinite depths of the divine mind, and then reveal them to us as far as is for our profit (Deuteronomy 29:29). This proves the personality and the God-head of the Holy Spirit. "Searcheth" indicates not ignorance, but accurate knowledge, and delight in the contemplation (Revelation 2:23). Contrast "the depths of Satan" (Revelation 2:24). He who has Christ revealed to him, has all things revealed in Him (1 Corinthians 3:22).