1 Corinthians 2:10

But God hath revealed them unto us
Should it be said, that since this wisdom is so hidden and mysterious, the doctrines of the Gospel are so unknown, so much out of the sight and understanding of men, how come any to be acquainted with them? The answer is ready, God has made a revelation of them, not only in his word, which is common to men, nor only to his ministers, but to private Christians and believers,

by his Spirit;
which designs not the external revelation made in the Scriptures, though that also is by the Spirit; but the internal revelation and application of the truths of the Gospel to the souls of men, which is sometimes ascribed to the Father of Christ. ( Matthew 16:17 ) sometimes to Christ himself, ( Galatians 1:12 ) and sometimes to the Spirit of Christ, ( Ephesians 1:17 ) and who guides into all truth, ( John 16:13 ) , and here to the Father by the Spirit:

for the Spirit searcheth all things, yea, the deep things of God;
which does not suppose any ignorance of these things in the Spirit, antecedent to his searching of them; but his complete and perfect knowledge of them; even as God's searching of the hearts of men expresses his omniscience, and through knowledge of all that is in them: the "all things" the Spirit searches into, and has a perfect knowledge of, do not design in the utmost extent everything which comes within the compass of his infinite understanding; but every thing that is in, or belongs to the Gospel of Christ, even the more mysterious and sublime, as well as the more plain and easy doctrines: for the "deep things of God" intend not the perfections of his nature, which are past finding out unto perfection by men; nor the depths of his wise and righteous providence; but the mysterious doctrines of the Gospel, the fellowship of the mystery which was hid in God, his wise counsels of old concerning man's salvation, the scheme of things drawn in his eternal mind, and revealed in the word.