Concise Bible Dictionary:
There are several Greek words translated “to know,” the principal of which are
(¹). οῖδα, signifying “inward conscious knowledge” in the mind; and
(²). γινώσκω, signifying “objective knowledge.” The latter passes into consciousness, but not vice versa. There are several passages in the New Testament in which both words occur, a study of which will show that the words are not used promiscuously, and need to be carefully considered.
Matt. 24:43. Know²² this, that if the goodman of the house had known¹ in what watch the thief would come, &c. The same distinction occurs in Luke 12:39.
Mark 4:13. Know¹ ye not this parable? and how then will ye know² all parables?
John 7:27. We know¹ this man whence He is; but when Christ cometh, no man knoweth² whence He is.
John 8:55. Ye have not known² Him; but I know¹ Him; and if I should say, I know¹ Him not, I shall be a liar like unto you: but I know¹ Him, and keep His saying.
John 13:7. What I do thou knowest¹ not now; but thou shalt know² hereafter.
John 21:17. Lord, thou knowest¹ all things; Thou knowest² that I love Thee.
Rom. 7:7. I had not known² sin, but by the law: for I had not known¹ lust, except the law had said, Thou shalt not covet.
1 Cor. 8:1-2. We know¹ that we all have knowledge². Knowledge² puffeth up, but charity edifieth. And if any man think that he knoweth¹ [Editors alter this into ²] anything, he knoweth² nothing yet as he ought to know².
2 Cor. 5:16. Henceforth know¹ we no man after the flesh: yea, though we have known² Christ after the flesh, yet now henceforth know² we Him no more.
Heb. 8:11. They shall not teach.... saying, Know² the Lord: for all shall know¹ Me, from the least to the greatest.
1 John 2:29. If ye know¹ that He is righteous, ye know² that every one that doeth righteousness is born of Him.
1 John 5:20. We know¹ that the Son of God is come, and hath given us an understanding, that we may know² Him that is true.
Both these words are employed for the Lord’s own knowledge. In Matthew 12:15, Jesus knew² (that they were plotting to destroy Him) having heard it. And in Matthew 12:25 Jesus knew¹ their thoughts—had the conscious knowledge of it. Respecting our knowledge of the person of Christ, in Luke 10:22, no one knows² who the Son is except the Father; but in Matthew 11:27, which is a parallel passage, neither of the above words are used, but ἐπιγινώσκω, which implies a certain objective knowledge, not a mere acquaintance with a person. The knowledge that is partial, and that shall vanish away, is the objective knowledge (1 Cor. 13:8-9); not the inward conscious knowledge. In 1 Corinthians 13:12 it is real knowledge in the future, ἐπιγινώσκω. The words—both (¹) and (²)—often occur separately in John’s gospel and epistles, and their use may be profitably studied in a Greek Testament or Concordance.