Does Mark 16:9-20 really belong in our Bibles?
"Some Bible scholars doubt the authenticity of 16:9-20, insisting that Mark did not write this portion. These verses are not found in two early manuscripts, the Vatican Codex and the Sinaitic Codex. However, they are found in the overwhelming majority of early manuscripts. Those who reject verses 9-20 have attempted to support their opinion by a process called hapax legomena, the citing of some terms found here and not elsewhere in the Gospel. It is one of the least scientific or scholarly methods used to critize authorship. The futility of such a process may be seen easily by applying it to an equal part of the writings of most any erudite scholar. Some of the same ones who reject these verses also say that Paul did not write Ephesians because they have found 36 words in that epistle, not found elsewhere in Paul's writings.
"The authenticity of these verses (16:9-20) should not be doubted: (1) They are found in nearly all Greek manuscripts and have been accepted in the church from the Second Century A.D. (2) Nothing in these verses contradicts anything in the rest of the Scriptures."
[The Complete Biblical Library Study Bible, Mark, Ralph W. Harris Executive editor, 1986.]
While The International Standard Bible Encyclopaedia takes the view that the ending of Mark is doubtful, it is interesting to note that they have this to say, "They are certainly very early, perhaps as early as 100 AD, and have the support of ACDXrdz, all late unicals, all cursives, most VSS and Fathers, and were known to the scribes of (aleph) and B, who, however, do not accept them."