Most modern critics are agreed that the last twelve verses of Mark 16 are not an integral part of his Gospel.  The are omitted by T [A]; not by the Syr. Ap. 94. V. ii.

The question is entirely one of evidence.

From Ap. 94. V., we have seen that this evidence comes from three sources:  (1) manuscripts (2) versions, and (3) the early Christian writers, known as "the Fathers". This evidence has been exhaustively analyzed by the late Dean Burgon, whose work is epitomized in the Nos. I-III, below.

I.  As To MANUSCRIPTS, there are none older than the fourth century, and the oldest two uncial MSS. (B and a, see Ap. 94. V.) are without those twelve verses.  Of all the others (consisting of some eighteen uncials and some six hundred cursive MSS. which contain the Gospel of Mark) there is not one which leaves out these twelve verses.

II.  As to the Versions:--

1.  THE SYRIAC.  The oldest is the Syriac in its various forms :  the "Peshitto" (cent. 2), and the "Curetonian Syriac" (cent. 3).  Both are older than any Greek MS. in existence, and both contain these twelve verses.  So with the "Philoxenian" (cent. 5) and the "Jerusalem" (cent. 5).  See note (*3) on page 136 - Ap 94.

2.  THE LATIN VERSIONS.  JEROME (A.D. 382), who had access to Greek MSS. older than any now extant, includes these twelve verses; but this Version (known as the Vulgate) was only a revision of the VETUS ITALA, which is believed to belong to cent. 2, and contains these verses.

3.  THE GOTHIC VERSION (A.D. 350) contains them.

4.  THE EGYPTIAN VERSIONS:  the Memphitic (or Lower Egyptian, less properly called "COPTIC"), belonging to cent. 4 or 5, contains them; as does the "THEBAIC" (or Upper Egyptian, less properly called the "SAHIDIC"), belonging to cent. 3.

5.  THE ARMENIAN (cent. 5), the ETHIOPIC (cent. 4-7), and the GEORGIAN (cent. 6) also bear witness to the genuineness of these verses.

III. THE FATHERS.  Whatever may be their value (or otherwise )as to doctrine and interpretation yet, in
determining actual words or their form, or sequence their evidence, even by an allusion, as to whether a verse or verses existed or not in their day, is more valuable than even manuscripts or Versions.

There are nearly a hundred ecclesiastical writers older than the oldest of our Greek codices; while between A.D. 300 and A.D. 600 there are about two hundred more, and they all refer to these twelve verses.

PAPIAS (about A.D. 100) refers to v. 18 (as stated by Eusebius, Hist. Ecc. iii. 39).

JUSTIN MARTYR (A.D. 151) quotes v. 20 (Apol. I. c. 45).

IRENAEUS (A.D. 180) quotes and remarks on v. 19 (Adv. Hoer. lib. iii. c. x.).

HIPPOLYTUS (A.D. 190-227) quotes vv. 17-19 (Lagarde's ed., 1858, p. 74).

VINCENTIUS (A.D. 256) quoted two verses at the seventh Council of Carthage, held under CYPRIAN.

The ACTA PILATI (cent. 2) quotes vv. 15, 16, 17, 18 (Tischendorf's ed., 1852, pp. 243, 351).

The APOSTOLICAL CONSTITUTIONS (cent. 3 or 4) quotes vv. 16, 17, 18.

EUSEBIUS (A.D. 325) discusses these verses, as quoted by MARINUS from a lost part of his History.

APHRAARTES (A.D. 337), a Syrian bishop, quoted vv. 16-18 in his first Homily (Dr. Wright's ed., 1869, i. p. 21).

AMBROSE (A.D. 374-97), Archbishop of Milan, freely quotes vv. 15 (four times), 16, 17, 18 (three times), and v. 20 (once).

CHRYSOSTOM (A.D. 400) refers to v. 9; and states that vv. 19, 20 are "the end of the Gospel".

JEROME (b. 331, d. 420) includes these twelve verses in his Latin translation, besides quoting vv. 9 and 14 in his other writings.

AUGUSTINE (fl. A.D. 395-430) more than quotes them.  He discusses them as being the work of the Evangelist MARK, and says that they were publicly read in the churches.

NESTORIUS (cent. 5) quotes v. 20 and

CYRIL OF ALEXANDRIA (A.D. 430) accepts the quotation.

VICTOR OF ANTIOCH (A.D. 425) confutes the opinion of Eusebius, by referring to very many MSS. which he had seen, and so had satisfied himself that the last twelve verses were recorded in them.

IV.   We should like to add our own judgment as to the root cause of the doubts which have gathered round these verses.

They contain the promise of the Lord, of which we read the fulfillment in Heb. 2:4.  The testimony of "them that heard Him" was to be the confirmation of His own teaching when on earth :  "God also bearing them witness, both with signs and wonders and divers miracles, and gifts of pneuma hagion (i.e. spiritual gifts.  See Ap. 101. II. 14), according to His own will."

The Acts of the Apostles records the fulfillment of the Lord's promise in Mark 16:17, 18; and in the last chapter we find a culminating exhibition of "the Lord's working with them" (vv. 3, 5, 8, 9).  But already in 1Cor. 13:8-13, it was revealed that a time was then approaching when all these spiritual gifts should be "done away".  That time coincided with the close of that dispensation, by the destruction of Jerusalem; when they that heard the Lord could no longer add their confirmation to the Lord's teaching, and there was nothing for God to bear witness to.  For nearly a hundred years (*1) after the destruction of Jerusalem there is a complete blank in ecclesiastical history, and a complete silence of Christian speakers and writers (*2).  So far from the Churches of the present day being the continuation of Apostolic times, "organized religion", as we see it to-day, was the work of a subsequent and quite an independent generation.

When later transcribers of the Greek manuscripts came to the last twelve verses of Mark, and saw no trace of such spiritual gifts in existence, they concluded that there must be something doubtful about the genuineness of the verses.  Hence some may have marked them as doubtful, some as spurious, while others omitted them altogether.

A phenomenon of quite an opposite kind is witnessed in the present day.

Some [believers in these twelve verses], earnest in their desire to serve the Lord, but not "rightly dividing the Word of truth" as to the dispensations, look around, and not seeing these spiritual gifts in operation, determine to have them (!) and are led into all sorts of more than doubtful means in their desire to obtain them.  The resulting "confusion" shows that God is "not the author" of such a movement (see 1Cor. 14:31-33).

(*1)  See Col. 1, opposite.

(*2)  Except the Didache, or Teaching of the Twelve, which is supposed to be about the middle of the second century, but which shows how soon the corruption of New Testament "Christianity" had set in.