Strong's exhaustive concordance

the long version

It has every word in the Bible; if you know a verse such as "Thy word is a lamp unto my feet" Take the word lamp, you look up the word lamp: it says that verse is in Ps 119:105 and it has the number 5216. Well you know that verse is in the Old Testament so 5216 would be in the Hebrew dictionary in the back of the book. Now the verse "Don't cast your pearls before swine" look up the word swine, it says that verse is in Mt 7:6 with a number of 5519, so you know it is in the New Testament, so 5519 would be in the Greek dictionary in the back of the book. The Old Testament was writen in Hebrew, the New Testament was written in Greek.