What do you intend, when you say that you “know” someone/something? You know who they are? You are close associates or friends? You are able to perform a task? You are acquainted with certain facts? You can quote something from memory? You can recognize an artifact or idea, speak a language, or understand a culture? The English language incorporates all of these “meanings” – and more – some of which may be contradictory — into a single word, “to know.”
The New Testament writers, in contrast, employ eight different words, all of which traditional translators have rendered simply as “know.” Is it any wonder that confusion can result? An evil spirit screams at Jesus, “I know you!” (Lk.4:34), yet later, the ultimate blessing of “eternal life” is attributed to “knowing” him (Jn.17:3)! The reader of the average English text has no clue that these are different words. Unfortunately, they don’t all sort out quite that easily, but we can clear up some of the fog with careful attention to vocabulary. In this study, correct understanding of the differences between the original words will probably not materially change one’s understanding of most passages, as much as it will enhance our appreciation for the message.
The most commonly used of all of these words is oida. It is the perfect tense form of the verb horao, “to see”, and occurs at least 285 times in the New Testament. Classical uses of oida are obviously connected to the concept of “seeing.” They include looking at or paying attention to something, “mental” sight or discernment, to behold or observe an object or event, or to be acquainted with a fact. This is not foreign to us: “Oh, I see!” is equivalent to “I get it!” “I understand.” In the New Testament, it is concerned primarily with information, which may or may not influence one’s life. “I know” (oida) may be an expression of confidence or expectation, as in Eph.1:18, but it need not. It may concern awareness of someone’s reputation (Rom.16:15, I Thess.1:5), or of an event or idea (like all 13 occurrences in Acts).
Ginosko, the second most frequent NT usage, (196 uses), usually presupposes more personal involvement with the person, event, or principle that is “known.” Classically, it included recognition, discernment, or opinion that results from personal experience or observation. The word was also used of the marital relationship. Frequently, the NT writers used it to refer to the simple identification of individuals (Lk.24:35), of recognition or understanding of events or people (Mt.24:43), or of “finding out” (Jn.12:9) information.
The difference between oida and ginosko is most easily seen in passages where both are used. For example, look at Jesus’ upper room conversation with Peter in Jn.13:7. To Peter’s protest at the apparent impropriety of a master washing the feet of disciples, Jesus replies, “You don’t know (ouk oidas) what I’m doing now, but you will understand/know (gnose) later.” And Peter did learn the lesson – by experience – quite well, as evidenced by his later instructions to the brotherhood (I Pet.4:10), “As each one has received a spiritual gift, serve each other with it.” You may also want to follow the interplay between oida and ginosko in John 7 and 8 or John 13 and 14, which is easily done by using Young’s concordance (see Word Study instructions), for further understanding of the different implications of the two words.
Epiginosko (the prefix epi is an intensifier) appears only 30 times translated “know”, 5 as “acknowledge”, and 3 as “perceive.” Classical definitions include to witness or observe, to recognize, to find out or discover, to become acquainted, or to decide or adjudicate. Many of the NT references are focused on recognition or identification (Mk.6:33 and parallels, Ac3:10, 9:30, 12:14, 19:34; Lk.24:16 and 31), or reassurance (Lk.1:4, II Cor13.5, Col.1:6, I Tim4:3). Peter’s warning takes on an even more serious tone, when he uses epiginosko (the stronger term) both times in II Pet.2:21: “It would be better for them never to have become acquainted with the way of justice, than having known it, to turn back ….”
Other words are less frequent, and less “loaded”:
Epistamai, classically to know how to do something, to understand a matter, to know as a fact, in Homer, to know for certain, or in Aristotle referring to scientific facts, in the NT usage refers primarily to information, primarily about an individual’s past history (Ac.20:18).
Proginosko (source of English “prognosis”), to know or perceive beforehand, usually without being told, occurs only five times, and it must be remembered that it refers to knowing, not causation, despite the distortion by some translators. (II Pet.3:17 and I Pet.1:2 use the same word.)
Sunoida, used only four times, refers to shared knowledge (the prefix sun- is the preposition “with”).
Diaginosko (source of English “diagnosis”) appears only once, in a legal investigation (Ac.24:22).
Agnoeo (source of English “agnostic”) – the “a” is a negative prefix – is used four times as “not knowing” (Ac13:7, and Rom.2:4, 6:3, and 7:1), and 10 times as “to be ignorant”. Please note that this ignorance does not presuppose hostility – simply “not knowing.”
It is the frequently used ginosko, oida, and epiginosko that need more attention than they commonly receive. Notice, please, that none are “inferior” to others in any way; they are simply different. Notice also that none of these contain any admonitions regarding intricate details of dogma or argument. And Jesus bluntly informed his curious disciples (Ac.1:7) that “it is not for you to know” (ginosko) a roadmap of the future!
Although oida usually refers to knowing or figuring out facts, Paul clearly expects it to inform one’s way of life. In Gal.4:16 he points out that when they did not “know” God, they followed lesser leaders, and in Eph.1:18, “knowing” one’s calling is supposed to motivate a godly life. Phil.4:12, often (mis)quoted, expresses the apostle’s confidence that in the power of God, he “knows how to” deal with any situation. It is not an expression of infallibility or omnipotence on his part — or ours!
Ginosko more commonly represents knowledge acquired by personal experience or relationship. It predominates heavily in Jesus’ prayer (Jn17). When Jesus is explaining the meaning of parables, or someone is referring to God’s understanding of a person’s situation, ginosko is usually (though not always) the choice.
It is clear that something more than passing acquaintance is intended in Paul’s prayer for the Ephesian brethren (Eph.3:19) that they may “know” (gnonai) the love of Christ, which vastly exceeds “knowledge” (gnoseos)! (The verb is wonderful! It is a form from which our “hyperbole” is derived!) A similar flavor occurs throughout John’s first letter. He is speaking of a very intimate involvement between Jesus and his people.
Epiginosko is usually reserved for very close acquaintance between people, or a thorough understanding of information.
All three are important ingredients or enablers of faithfulness, which, in the final analysis, is intended to be the goal of all our pursuit of “knowledge”: that we may experience the full measure of the maturity/completeness that our King intends for us.
May we continue to grow in that knowledge!
The Pioneers' New Testament 
Loved this article. Over the years I have looked at the differences of ‘know’ in the N.T. My study of recent, comparing it to the Hebrew ‘know’ [‘yada’] as found in Ps. 46:10, “Be still and know that I am God…” It too is founded in relationship and experience. These two elements are becoming ‘lost’ in our culture, if we ‘see’ it on YouTube, or quoted in Facebook, we have determined we ‘know’ it. Thank you for the in-depth study. – dede
Thank you so much this is so helpful and I am amazed that many who teach have not come to these conclusions. I especially appreciate that you note how of the 3 none is greater than the other this really helps me so much. As a small group leader I am blessed by this and encourage you to keep doing God’s work.