Strong's Exhaustive Concordance of the Bible, generally known as Strong's Concordance, is a concordance of the King James Bible (KJV) that was constructed under the direction of Dr. James Strong (1822–1894) and first published in 1890. Dr. Strong was Professor of exegetical theology at Drew Theological Seminary at the time. It is an exhaustive cross-reference of every word in the KJV back to the word in the original text.

Unlike other Biblical reference books, the purpose of Strong's Concordance is not to provide content or commentary about the Bible, but to provide an index to the Bible. This allows the reader to find words where they appear in the Bible. This index allows a student of the Bible to re-find a phrase or passage previously studied or to compare how the same topic is discussed in different parts of the Bible.

Strong's Concordance includes:
The 8674 Hebrew root words used in the Old Testament. (Example: Hebrew word #582 in Strong's)
James Strong did not construct Strong's Concordance by himself; it was constructed with the effort of more than a hundred colleagues. It has become the most widely used concordance for the King James Bible.

Each original-language word is given an entry number in the dictionary of those original language words listed in the back of the concordance. These have become known as the "Strong's numbers". The main concordance lists each word that appears in the King James Bible in alphabetical order with each verse in which it appears listed in order of its appearance in the Bible, with a snippet of the surrounding text (including the word in italics). Appearing to the right of scripture reference is the Strong's number. This allows the user of the concordance to look up the meaning of the original language word in the associated dictionary in the back, thereby showing how the original language word was translated into the English word in the KJV Bible.

New editions of Strong's Exhaustive Concordance of the Bible are still in print (in 2007). Additionally, other authors have used Strong's numbers in concordances of other Bible translations, such as the New International Version NIV and ASV American Standard Version. These are often also referred to as Strong's Concordances.

Although the Greek words in Strong's Concordance are numbered 1–5624, the numbers 2717 and 3203–3302 are unassigned due to "changes in the enumeration while in progress". Not every distinct word is assigned a number, but only the root words. For example, αγαπησεις is assigned the same number as αγαπατε — both are listed as Greek word #25 in Strong's "αγαπαω". - Try it here:
Strong's Concordance Hebrew Greek Lexicon

Strong's Greek Concordance

Strong's Greek concordance is a very useful tool for studying Bible verses. It takes every single word of the King James Version and lists where each word can be found in the Bible. It is useful for locating scripture verses that you know the words to, but don't know the book, chapter and verse. For example, let's say that you know of a verse that says our hairs are numbered. You could look up the word "numbered" in a Strong's Concordance and it would give you a listing of all the verses that contain the word "numbered". You would then find Matthew 10:30, where Yahushua said that "the very hairs of your head are all numbered". This is a Greek word in Strongs concordance. Also beside each verse reference there is a number. That number represents a Hebrew word (if in the Old Testament) or Greek word (if in the New Testament). In the back of the book it lists Hebrew and Greek words used to translate the bible into English. Each has a a number beside them so that we may only need to know the number to locate a Greek or Hebrew word. Then we can do a word study by reading the meaning of the original word. Whenever referring to a number in the Strong's concordance, you can look up the number for yourself in the Greek in Strong's Lexicon or other lexicons that use Strong's numbers to verify everything.
The 5624 Greek root words used in the New Testament. (Example: Greek word #3056 in Strong's)

Strong's Greek Concordance

Strong's Concordance is not a translation of the Bible it may be used as a translation tool. The use of Strong's numbers is not a substitute for professional translation of the Bible from Hebrew and Greek into English by those with formal training in ancient languages and the literature of the cultures in which the Bible was written.

Since Strong's Concordance identifies the original words in Hebrew and Greek, Strong's Numbers are sometimes misinterpreted by those without adequate training to change the Bible from its accurate meaning simply by taking the words out of cultural context. The use of Strong's numbering system does not consider figures of speech, metaphors, idioms, common phrases, cultural references, references to historical events, or alternate meanings used by those of the time period to express their thoughts in their own language at the time. As such, professionals and amateurs alike must consult a number of contextual tools to reconstruct these cultural backgrounds. Many scholarly Greek and Hebrew Lexicons (e.g., Brown Driver Briggs Hebrew Lexicon, Thayers Greek Dictionary, and Vines Bible Dictionary) also use Strong's numbers for cross-referencing, encouraging hermetical approaches to study.
As it says in Exodus 20:11, the earth was made in 6 days. Checking the Hebrew word for days at H3117

Strong's Concordance is different from a regular Bible Concordance which usually does not contain references to the Greek and Hebrew text.

Strong's Concordance with Hebrew and Greek Lexicon bring you these Bible verses:

John 13:34
A new commandment I give unto you, That ye love one another; as I have loved you, that ye also love one another.

Job 12:9
Who knoweth not in all these that the hand of the LORD hath wrought this?

2 Timothy 3:16
All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness:

Genesis 8:22
While the earth remaineth, seedtime and harvest, and cold and heat, and summer and winter, and day and night shall not cease.