In four verses in the synoptic Gospels, the reader is presented with evidence of what seems to be a disagreement between the Evangelists about the rules of syntax. Each of the four verses, using slightly different wording, reproduces one of Jesus’ sayings in which he uses the expression “Heaven and earth will pass” or “Until heaven and earth shall pass”. Matthew puts the verb in the singular, despite the two subjects, while Mark and Luke put it in the plural.
ἀμὴν γὰρ λέγω ὑμῖν, ἕως ἂν παρέλθῃ ὁ οὐρανὸς καὶ ἡ γῆ, ἰῶτα ἓν ἢ μία κεραία οὐ μὴ παρέλθῃ ἀπὸ τοῦ νόμου ἕως ἂν πάντα γένηται. (Matt 5:18)
ὁ οὐρανὸς καὶ ἡ γῆ παρελεύσεται, οἱ δὲ λόγοι μου οὐ μὴ παρέλθωσιν. (Matt 24:35)
ὁ οὐρανὸς καὶ ἡ γῆ παρελεύσονται, οἱ δὲ λόγοι μου οὐ μὴ παρελεύσονται. (Mark 13:31 = Luke 21:33).
Checking at Alan Bunning’s Center for New Testament Restoration (two links below), as far as I can see all the manuscripts without exception have the verb in the singular (παρέλθῃ) in Matt 5:18, while in Matt 24:35 at least one MS has the verb in the plural (παρελεύσονται).
My first question, then, is this: Are both constructions equally correct, as far as the syntax is concerned, with each evangelist expressing a stylistic preference only?
However, a supplementary question then arises, concerning Jerome and his later editors. The Vulgate text retains Matthew’s singular verb in 5:18 but changes it to the plural in 24:35. Why would that be? (This arrangement, by the way, is left untouched in the Nova Vulgata.)
Amen quippe dico vobis, donec transeat cælum et terra, jota unum aut unus apex non præteribit a lege, donec omnia fiant. (Matt 5:18)
Cælum et terra transibunt, verba autem mea non præteribunt. (Matt 24:35)
Cælum et terra transibunt, verba autem mea non transibunt. (Mark 13:31= Luke 21:33)
https://greekcntr.org/collation/?v=40005018
https://greekcntr.org/collation/?v=40024035