There are few ancient manuscript copies of the Old Testament. When copies of the Hebrew text were made, the Jews would ceremoniously destroy the old, worn-out manuscript.
However, the manuscript copies we have today of the Hebrew text of the Old Testament are extremely accurate. The oldest, complete Hebrew manuscript of the Old Testament dates back to only AD900, which leaves a gap of 1,300 years between the time when the Old Testament was completed in 400BC with the writing of Malachi.
But with the discovery of the Dead Sea Scrolls, (dating to around 125 BC) we have been given dramatic proof of the accuracy of the Old Testament manuscript copies.
The Dead Sea Scrolls were found in a cave in Palestine in 1047 by a Bedouin shepherd boy. The scrolls were found preserved in a number of clay pots that had been hidden in the cave for safekeeping by the Jews who lived in the nearby community at Qumran which was destroyed by the Romans around AD 70. The scrolls themselves were much older and were written approximately 125 years before Christ.
Among other things, the Dead Sea Scrolls contain portions of the Book of Isaiah, particularly Chapter 53. It has been said that of the 166 words in Isaiah 53 only 17 letters are in question.
Ten of these letters are simply a matter of spelling which does not affect the meaning. Four more letters are minor stylistic changes, such as conjunctions. The remaining three letters comprise the word "light," which is added in verse 11 and does not affect the meaning greatly. Furthermore, the word "light," is found in the Septuagint version of Isaiah 53, (the Greek translation of the Hebrew scriptures made between 285-246 B.C.)
Therefore in Isaiah Chapter 53, of the 166 words in that chapter, there is only one word consisting of three letters
which are in question between the Dead Sea Scrolls (125 B.C.) and the oldest existing Greek manuscript (AD 900).
That amounts to a question over one word after approximately 1,300 years of copying the text hundreds of times.
The Septuagint translation of the Old Testament from Hebrew to Greek, which was done between 285 and 246B.C., also provides excellent evidence concerning the reliability of the Old Testament scriptures.
The word "Septuagint" means "seventy" and is designated by the Roman numerals LXX (70), since there were seventy Jewish scholars involved in translating the Hebrew scriptures into Greek.
This translation is very close to the oldest known Hebrew manuscript (The Masoretic Text A.D.916), proving that after 1,300 years the Hebrew Massoretic text is a highly accurate and dependable copy.
Jewish scribes such as the Talmudists (AD 100-500) and the Massoretes (AD 500-900) took special care to copy every manuscript accurately. Among their rules for copying manuscripts, they could not copy a single word or letter from memory but had to copy each letter and every "jot and tittle" by first looking at the letter in the existing manuscript, then writing it in the new copy exactly as it appears in the existing manuscript.
To safeguard against scribal slips, they counted the number of times each letter of the alphabet appears in each book and compared that to the new copy. If there was a discrepancy, they would destroy the new copy and start over again. They also calculated the middle letter of the Pentateuch and the middle letter of the entire Hebrew Bible, if there was a discrepancy with the new copy, it was likewise destroyed and they would begin again. When everything added up with the new manuscript, the new copy was held to be an exact duplicate, and the old manuscript was destroyed.
Image Source: Pinterest; Text source: Searching the Scriptures
Genesis 17:7-8 (NKJV)
And I will establish My covenant between Me and you and your descendants after you in their generations, for an everlasting covenant, to be God to you and your descendants after you. Also I give to you and your descendants after you the land in which you are a stranger, all the land of Canaan, as an everlasting possession; and I will be their God.”