The Sinaiticus is one of two manuscripts which are the one's called by many "the oldest manuscripts." The other, is the Vaticanus. This is a prime example of "oldest is not always best."
The Sinaiticus is also known and referred to as Codex Aleph, a Hebrew Letter. See The Terminology for an understanding of the names and different terms used to represent manuscripts.
When referring to the Sinaiticus as a historical manuscript witness, it is most often coupled with the Vaticanus. They both are alleged to have been dated around AD 350. And both, are the major building blocks of most Modern Versions of the New Testament. They are used because of their age, as so many claim them to be the oldest and thus most reliable. However, sadly this is untrue. As human witnesses are found to be liars, or Truthful, by the words they speak and if they agree amongst other witnesses, so are manuscript witnesses. This is how we rightly determine whether a manuscript is worthy to be used for our Bible.
Found by a Constantin Tischendorf in St. Catharine's Monastery in the Sinai desert, Codex Aleph was written on vellum in book form (hence the name "codex"). Its pages are about 15" by 13.5" and on each page are four columns of Forty-eight (48) lines. Sadly, when reading the Sinaiticus, one will find many mistakes which are neglected and ignored by those who love it. It contains extra-biblical books such as "Epistle of Barnabas," "Didache," and "Shepherd of Hermas." Tischendorf actually is said to have rescued the manuscript from the trash at the monastery! This sheds some doubt on the manuscript, why would such a "valuable" manuscript be in the trash? Obviously someone in the monastery saw it, deemed it garbage, and put it with the rest of the trash.
There is a rumor that it was actually written by Constantine Simonides, a Greek from Syme. He told the world, that he actually scribed codex Aleph from 1839-1840! As to whether this is true or not, is of little importance because only to the foolish, worldly, "scholars" is such a thing good or bad to them. As they believe oldest is best, this would devastate them. However, the context of Codex Sinaiticus itself is enough to discredit it, not just its age.
Of Codex Aleph, Dr. F.H.A. Scrivener says in his work A Full Collation of the Codex Sinaiticus:
The Codex is covered with such alterations . . . brought in by at least ten different revisors, some of them systematically spread over every page, others occasional or limited to separated portions of the manuscript, many of these being contemporaneous with the first writer, but for the greater part belonging to the sixth or seventh century.
Dr. Scrivener also says of Tischendorf, that he is of the least reliable in discernment and accuracy. Obviously both the person who supposedly found the manuscript, and the manuscript itself, aren't reliable!
Remember that to tell a good witness from a bad one, a witness is compared to other witnesses, more rightly other witnesses which have stood the tests and proven themselves to be true and accurate! The same with Codex Sinaiticus (Aleph). Sadly, when put to the test, the Sinaiticus disagrees with all other extant manuscripts, save a handful. The Sinaiticus has in the Gospels alone over 1,400 readings which are only found within itself, affecting more than 2,600 words.
Many of the differences the Sinaiticus has from all other manuscripts, are that it nearly always says the exact opposite! One example of this is a reading of 1 Corinthians 13:5 which says "charity seeketh not her own", the Sinaiticus reads "love does not seek that which is not hers" which is indeed the opposite meaning of the True Word of God!
The Sinaiticus often is said to contain the best readings, while it is neglected to be told how contrary it is to all but a handful (perhaps 40 out of 500) manuscripts. Erasmus, when studying the manuscript let on that he believed the manuscript only agreed with those few, because those few were pressured into being rewritten to agree with the Codex!
Compared to those manuscript witnesses proven to be True, the Sinaiticus in the Gospels alone 3,455 words are omitted, 839 words are added, 1,114 words are substituted, 2,299 words are transposed, and 1,265 are modified! Note, this is just in the Gospels alone, four books of the New Testament!
All in all, the most shocking of information is the fact that the Sinaiticus not only was revised and changed over the time, by at least Ten (10) different people, but it was done so very carelessly. It has many places where even words and phrases are repeated one right after the other! The conclusion of the matter has proven that the Sinaiticus, which is so very often referred to in Biblical footnotes as the "oldest manuscripts," is highly unreliable even according to secular historians.
DefinitionsExtra-Biblical--Excluded from the Bible. Non-Biblical
Extant Manuscripts--Manuscripts we know of today
Transposed--Changed position in the sentence or context, many times changing the meaning