What is coveneutics, and how important is it to understand the Bible?
As it pertains to understanding the Scriptures, the word hermeneutics relates to, “the study of the principles of interpretation concerning the books of the Bible.”  Most people encounter the tension between what the Bible says and seeking to ascertain what it means. Since the Bible contains a vast array of literary genres, the complexity of applying a consistent method of interpretation to various passages increases. Concerning this complexity, one writer correctly observes:
Any method of interpretation is dangerous if it perverts the true meaning of scripture, and of course, the ultimate test as to whether the true meaning of scripture has been ascertained will be in the field of harmony and consistency. Any principle of interpretation that fails to advance harmony of thought and purpose in every related field of study must be considered as false. God’s eternal purpose is so constituted and unfolded in the scriptures, that the only right method of interpretation can be advanced entirely free of contradiction, inconsistency, or disharmony. The right method will not only meet the demands of the immediate scripture or context but also of every related scripture or context. 
The fact that the ‘right method’ of interpretation must necessarily involve freedom from “contradiction, inconsistency, or disharmony” means the need for vigilance from those who are “accurately handling the word of truth” (II Tim. 2:15). Only the proper application of those principles of interpretation that takes into consideration every aspect of God’s “purpose of the ages” (Eph. 3:11), both the “natural” and the “spiritual” (I Cor. 15:46) will “meet the demands of the immediate scripture or context, but also of every related scripture or context.”
Stated simply, coveneutics is that method of Biblical interpretation that recognizes the overarching priority afforded to covenant, from Genesis to Revelation.  While covenant is a word used throughout Scripture, few understand the importance of its foundational basis (Gen. 6:18; 9:9, 11, 12, 13, 15-18; 17:2, 4, 7, 9-11, 13, 14, 19, 21; 21:27, 32; 26:28 et al). The word covenant is found 313 times in the Old and New Testaments and describes the terms of the relationship between God and His people. Covenant is God’s word, His “sworn oath” (Heb. 6:13-20), with conditions, promises, and consequences (positive or negative) for those who enter into it. Covenant implies the inseparable bond that exists between God and those to whom entrance into it is given. Those inside the covenant are amenable to it, while those outside are not.
The concept of coveneutics includes the proper relationship that exists between the “natural” aspects of covenant, and also the “spiritual” aspects to which it points (I Cor. 15:46). The terms “natural” and “spiritual” are not mutually exclusive but rather complementary in scope, intent and nature. The use of the “natural” by the inspired writers of the Bible was always with a view toward the ultimate fulfillment in the manifestation of those “spiritual” realities to which they pointed. The relationship between the Old and New Testaments is one of “promise” and “fulfillment” thus what was contained in types, shadows and other figures of speech in the Old Testament would find their realization is the actual fulfillment taking place in the New Testament (Col. 2:17; Heb. 8:5; 10:1). Once such contrast was the relationship between the codified “law” and its fulfillment in the manifestation of “grace and truth.” John writes: “For of His [Christ] fullness, we have all received, and grace upon grace. For The Law was given through Moses, grace and truth were realized through Jesus Christ” (John 1:16, 17). The mission of Jesus was to bring about the fulfillment of both “the law” and “the prophets” (Matt. 5:17, 18), at the time when “all things which are written” were fulfilled in 70 CE (Luke 21:22).
NATURAL AND SPIRITUAL
Coveneutics involves the interconnectedness between the “natural” and the “spiritual” as seen throughout the Scriptures. Both the world above and the world below (John 3:31; 8:23; 19:11), and the things pertaining to the “natural” and the “spiritual” existed concurrently from the book of Genesis onward. The unfortunate disparity that exists today in modern methodology as applied to Biblical interpretation is that most scholars tend to take an “either/or” rather than a “both/and” approach to the text. It is out of the “natural” aspect of Scripture that arises the “spiritual” application and meaning of the text.
The difference between this methodology and that of the allegorical or symbolic approach is the recognition that the picturesque language of the Bible is rooted in the historical narrative, from which proper applications of symbolism can be rightly ascertained. Those who see the Genesis creation account as only “natural” often miss the flow of God’s redemptive intention that is realized throughout the course of history. Those who see the Genesis creation account as only “spiritual” often miss the progression of actual history as it moves toward the time of its grand and glorious consummation. Only when both aspects are given due respect and proper consideration does the hidden message of the Bible become evident.
The Old Testament examples of the relationship between “natural” and “spiritual,” “shadow” and “reality” are demonstrated in the unfolding events in the case of the covenant promises that became part of Israel’s history and national economy. The Old Covenant was the “natural” aspect, while the New Covenant was the “spiritual” aspect from the standpoint of “promise” and “fulfillment”.
 “Hermeneutic” in Wikipedia (http://en.wikipedia.org/wiki/Hermeneutics).
 Max R. King, The Spirit of Prophecy (Parkman Road Church of Christ, Warren, Ohio: 1971 edition), 27.
 “Coveneutics” is a word coined by Larry Siegle to describe the inseparable relationship between the “natural” and “spiritual” aspects of Biblical interpretation (I Cor. 15:46).