We don't know that, actually. The "inspired text" is whatever Matthew originally penned. Tradition indicates he wrote it in "Hebrew" (which may mean Aramaic, but certainly doesn't mean Greek).
An Aramaic/Syriac textual tradition of Matthew still exists, called the Peshitta. (Whether it's based on an Aramaic original, or the Aramaic original, is not clear.)
Well I know that is what the Jehovah Witness believe
From The Wycliffe Bible commentary: Matthew, Pfeiffer, C. F
Composition and Date. The great frequency of citations and allusions to Matthew found in the Didache, Epistle of Barnabas, Ignatius, Justin Martyr, and others attests its early composition and widespread use.
The literar connections of this Gospel must be considered in its relations to the other Synoptics, and also to the statement of Papias that "Matthew wrote the words in the Hebrew dialect, and each one interpreted as he could" (Eusebius Ecclesiastical History 3.39). Many have explained Papias’ statement as referring to an Aramaic original from which our Greek Gospel is a translation.
Yet our Greek text does not bear the marks of a translation, and the absence of any trace of an Aramaic original casts grave doubts upon this hypothesis. Goodspeed argues at length that it would be contrary to Greek practice to name a Greek translation after the author of an Aramaic original, for Greeks were concerned only with the one who put a work into Greek. As examples he cites the Gospel of Mark (it was not called the Gospel of Peter) and the Greek Old Testament, which was called the Septuagint (Seventy) after its translators, not after its Hebrew authors (E. J. Goodspeed, Matthew, Apostle and Evangelist, pp. 105, 106).
Thus Papias is understood to mean that Matthew recorded (by shorthand?) the discourses of Jesus in Aramaic, and later drew upon these when he composed his Greek Gospel. Though it is surely possible that Mark was written first, and may have been available to Matthew, there was no slavish use of this shorter Gospel by Matthew, and many have argued for the complete independence of the two books.
New Bible commentary, Matthew, Carson, D. A.
Authorship and date
Early Christian tradition unanimously attributed this gospel to the authorship of Matthew the apostle, the former tax-collector of Capernaum, whose call it records in 9:9 (Mark and Luke call him Levi). There was also a persistent tradition that it was written originally not in Greek but in Hebrew or Aramaic. Both of these traditions are doubted by most modern scholars.
The Greek of the gospel as we know it does not read like ‘translation Greek’, and the close literary relationship of Matthew with the (Greek) gospels of Mark and Luke makes its origin in any other language unlikely. It is quite possible that Christians in the first few centuries ad were familiar with a Hebrew or Aramaic work which was traditionally associated with Matthew, but unlikely that it was our gospel. Papias, the earliest writer to mention Matthew’s writing, attributes to him a compilation of ‘sayings’ in Hebrew or Aramaic, and some believe that he was referring not to the gospel we know but to one of its sources (perhaps the source ‘Q’ which many believe was used by the authors of Matthew and Luke; see the relevant section in ‘Reading the gospels’). But Papias’ statement is too brief to be clear, and its original context is unknown.
If it is improbable that Matthew’s gospel was written in Hebrew or Aramaic, can we take the other aspect of early tradition, the identity of the author as Matthew the apostle, any more seriously? Or does Papias’ statement suggest that this tradition arose in connection with a document other than our gospel? We cannot be sure, but the writers of the early Christian centuries offer us no other candidate for authorship, and a tradition which is both early and unanimous should not be simply assumed to be false unless the nature of the book itself makes it clearly inappropriate.
The Bible knowledge commentary, Walvoord, J. F.
The Original Language of the First Gospel.
While all the extant manuscripts of the First Gospel are in Greek, some suggest that Matthew wrote his Gospel in Aramaic, similar to Hebrew. Five individuals stated, in effect, that Matthew wrote in Aramaic and that translations followed in Greek: Papias (A.D. 80-155), Irenaeus (A.D. 130-202), Origen (A.D. 185-254), Eusebius (fourth century A.D.), and Jerome (sixth century A.D.).
However, they may have been referring to a writing by Matthew other than his Gospel account. Papias, for example, said Matthew compiled the sayings (logia) of Jesus. Those "sayings" might have been a second, shorter account of the Lord’s words, written in Aramaic and sent to a group of Jews for whom it would have been most meaningful. That writing was later lost, for no such version exists today.
The First Gospel, however, was probably penned by Matthew in Greek and has survived until today. Matthew’s logia did not survive, but his Gospel did. This was because the latter, part of the biblical canon and thus God’s Word, was inspired and preserved by the Spirit of God.
Matthew, J. W. McGarvey, p8
2. The Language
There has been much difference of opinion among scholars as to whether Matthew originally wrote his narrative in Greek, or in the Hebrew dialect of his age. The most satisfactory statement of the evidence pro and on accessible to the general reader may be found in Smith's Bible Dictionary, Art. MATTHEW, gospel. or. The essential facts in the case are the following: All of the ancient writers, whose extant writings allude to the question, represent Matthew as having written a narrative in Hebrew; but not one of them claims to have seen it except Jerome, and he subsequently expresses doubt as to whether the book which he saw under this name was the genuine Matthew. If a genuine Hebrew narrative at anytime existed, it perished with the age which gave it birth. All of the writers just named were familiar with the Greek Matthew; and none of them speak of it as a translation. A large majority of the modern writers regard the Greek as the original, and it is a singular confirmation of the correctness of this opinion that Alford, who, in the first edition of his commentary, took ground in favor of a Hebrew original, in the later editions acknowledges that he has been constrained to abandon that position. God has preserved the greek text of Matthew, not a fragment of any of his writings in "hebrew" remains Gospel or notes.
We can be sure that the Holy Spirit preserves the word of God as HE so desires. That which God ordained remained, THE INSPIRED TEXT .
...6. The Peshitta Syriac translation of the New Testament in Matthew 16:18 uses kepha' for both Greek words petros and petra. Is this accurate, or could it be a mistranslation of the original Greek Text?
7. The proper translation of Petros is Ke'pha'. On this we have the authority of the Word of God itself in the Greek original of the New Testament, where the name "Ke'pha" (in the English Bible "Cephas") is six times given as the Aramaic equivalent to Petros for the name of Simon bar Jonas. (John 1:42; 1Corinthians1:12; 3:22; 9:5; 15:5; Galatians 2:9) So, we can say, based upon the authority of the original Greek of the New Testament that Petros, the name given to Simon bar Jona by the Lord Jesus (John 1:42) is the correct translation of the Aramaic/Syriac word Ke'pha'. Greek: Petros = Aramaic: Ke'pha' ("Cephas")
But what of the Greek word Petra? Is it correctly translated as Ke'pha'?
There is nowhere in the Greek New Testament where the word Ke'pha' is given as the correct translation of the Greek word Petra. In order to determine the Syriac/Aramaic word which best translates the Greek word Petra we will have to look at the translations of the Greek New Testament which were made in the first five centuries of the Christian Church to determine how the Greek word Petra was understood.
Greek: Petra = Aramaic: ?8. In the Peshitta Syriac New Testament the Greek word "PETRA" is translated by the Aramaic word SHU`A' as in Matthew 7:24-25 meaning a massive rock or a boulder.
PETRA is used 16 times in the Greek New Testament:
Of those times it is translated in the Peshitta Syriac
9 times by the word SHU`A' ,
6 times by the word KE'PHA' and
1 time by the Hebrew root word 'ABENA'
Of the ten times PETRA is used in the Gospels it is translated:
7 times by the word SHU`A'
(Mt.7:24, 25; Mk.15:46; Lk 6:48[2x];8:6, 13)
3 times by the word KE'PHA'
(Mt.16:18; 27:51; 27:60)Of the three times KE'PHA' is used to translate PETRA in the Gospels:
[1] in Mt. 27:60 the parallel passage in Mark's gospel (Mark 15:46) more correctly uses SHU`A' to translate PETRA.
[2] in Mt. 27:51 the word KE'PHA' is used to describe the rocks (plural) which were broken at the earthquake when Christ died (and hence, these rocks became movable)
[3] the other passage is Mt. 16:18 where KE'PHA' is used to translate both PETROS and PETRA.
In all other places in the Gospels the Greek word PETRA is translated by the Syriac word SHU`A', meaning "a massive rock."
KE'PHA' is used in the Syriac N.T. as the translation of both the Greek words LITHOS and PETROS.
The Greek word LITHOS, which means "a stone" (generally of a size which could be picked up or moved) is ALWAYS translated by the Syriac word KE'PHA'.
As LITHOS in classical Greek is the common prose word for "a stone" (see the quote from Liddle and Scott's Lexicon, above) and PETROS is more common in poetry, this shows that the definition of KE'PHA' as "a stone" is correct. The Syriac KE'PHA' is equivalent to the Greek LITHOS, a movable stone.
KE'PHA' IS ALWAYS USED TO TRANSLATE THE GREEK WORD LITHOS.
SHU'A IS THE MORE USUAL AND CORRECT SYRIAC WORD TO TRANSLATE THE GREEK WORD PETRA.
KE'PHA IS A MOVABLE STONE = LITHOS / PETROS.
SHU'A IS A MASSIVE ROCK = PETRA.
The Syriac word SHU`A' is NEVER used to translate the Greek word LITHOS.
Because a LITHOS is NOT a large massive rock, but a SHU`A' is.
The Syriac KE'PHA' is correctly used to translate the Greek words LITHOS and PETROS because these are movable stones.9. The fact that the Greek text of the New Testament uses two separate Greek words in the passage [Matthew 16:18] indicates that any underlying Aramaic/Syriac original (if there was one, AND THIS IS FAR FROM PROVEN) also must have used two separate words.
Conclusion
a. A reconstructed Aramaic/Syriac of the passage would properly be:
"You are KE'PHA' (a movable stone) and upon this SHU`A' (a large massive rock) I will build my church."
This is in exact correspondence to the original inspired Greek text:
"You are PETROS (a movable stone) and upon this PETRA (a large massive rock) I will build my church."b. The Peshitta Syriac New Testament text, at leaast in its extant MSS, mistranslated the passage in Matthew 16:18, incorrectly using the Syriac word KE'PHA' for both Greek words PETROS and PETRA.
Cordially,