What does it mean to know something? (1Jn 5:13) How do I know truth? (2Ti 3:7) I think I know a few things, but how complete is my understanding? (1Co 8:2) How do I grow in knowledge? (2Pe 1:5) How do I measure this? (2Co 11:6) Why is this important? (Pr 2:3-5)
The theory of knowledge is called Epistemology; it’s how we think about thinking, what we know about knowing, the study of study, what it means to have meaning.
Knowing some proposition p requires three things:  p must be true,  we must believe p, and  we must have justification for this belief. (1Pe 3:15) To have knowledge then is to have a conviction of the nature of reality based upon reason: our ability to correctly interpret data (facts, evidence) relating to p which we perceive through our senses.
Conviction is necessary in knowledge but insufficient; without good reason, we merely have an opinion; to claim knowledge in this case is merely arrogance, conceit (Pr 26:16) and presumption (Ps 19:13), even if we happen to be correct. All actual knowledge requires insight, that we correctly perceive connections and relationships between facts such that we understand reality.
This knowing can’t merely be chemical reactions in our brains or hormones making us feel certain ways: molecules can’t think, reason or understand. Real apprehension of the nature of reality is metaphysical, above and beyond Nature itself. (Php 3:12) It’s only possible because God enables us to do it (Mt 13:11), equipping the soul to enjoy Him within Nature; it’s part of being created in His image (Ge 1:27); knowing anything is part of knowing Him (2Ti 1:12) – it’s what we’re made for. (Php 3:8)
Since all knowledge reflects reality, rooted in the immutability (Mal 3:6) of JEHOVAH Himself (Ro 11:36), and since reality can’t be inconsistent with itself, all knowledge must be consistent with all other knowledge. Thus, by carefully leveraging the knowledge we already have, we can acquire more.
We can only acquire knowledge by collecting and correctly interpreting a reasonable amount of data relating to a given proposition, and finding no (zero) contradiction or inconsistency within this data. We rightly claim knowledge only under these conditions, and we ought to do so (if words are to have meaning), even though we’re finite, unable to collect all possible data relevant to any given proposition. (1Co 13:12) The key here being reasonable: deception ought to arise only as a consistently inaccurate, holistic depiction of reality is presented to our senses.
Repenting, admitting to being wrong, in error, of having an incorrect understanding of reality, is enabled and facilitated by acquiring additional facts which contradict or are inconsistent with our current perception of reality. This requires recognizing that we haven’t been as thorough as we ought in  acquiring a reasonable amount of data, and/or  correctly interpreting this evidence.
Incorporating new facts with what we already know, and developing a world view that squares with all evidence available to us, is how we grow in wisdom and understanding. The alternative, ignoring facts which contradict our view, or employing false reasoning as we interpret facts which inconvenience us, is dishonest (Ro 1:18); God condemns both as a love of darkness. (Jn 3:19)
We’re each responsible to both hate vain thinking (Ps 119:113) and also to have an accurate perception of reality (Ja 1:16), to love truth (2Th 2:10) and cry after knowledge so we can be more aligned with God. (Pr 1:28-29) This implies God has provided sufficient evidence for us to know Him (Ro 1:20), and also the ability to reason correctly as we interpret it. (Is 1:18)
Knowledge begins with the fear of God. (Pr 1:7) As we seek to know Him and about Him in humility and love, the Father Himself gives us knowledge and understanding (Pr 2:6) and Christ reveals truth to us. (Jn 18:37)
It’s a journey, for sure, the Way (Jn 14:6), a lifestyle … one with purpose and destiny … the only one worth taking.