Josias begat Jechonias, etc. - There are three considerable difficulties in this verse.
1. Josias was not the father of Jechonias; he was only the grandfather of that prince: 1-Chronicles 3:14-16.
2. Jechonias had no brethren; at least, none are on record.
3. Josias died 20 years before the Babylonish captivity took place, and therefore Jechonias and his brethren could not have been begotten about the time they were carried away to Babylon.
To this may be added a fourth difficulty, viz. there are only thirteen in this 2nd class of generations; or forty-one, instead of forty-two, in the whole. But all these difficulties disappear, by adopting a reading found in many MSS. Ιωσιας δε εγεννησε τον Ιωακειμ· Ιωακειμ δε εγεννησε τον Ιεχονιαν. And Josias begat Jehoiakim, or Joakim, and Joakim begat Jechonias. For this reading, see the authorities in Griesbach. Josiah was the immediate father of Jehoiakim (called also Eliakeim and Joakim) and his brethren, who were Johanan, Zedekiah, and Shallum: see 1-Chronicles 3:15. Joakim was the father of Joachin or Jechonias, about the time of the first Babylonish captivity: for we may reckon three Babylonish captivities. The first happened in the fourth year of Joakim, son of Josiah, about A. M. 3398. In this year, Nebuchadnezzar, having taken Jerusalem, led a great number of captives to Babylon. The second captivity happened under Jechoniah, son of Joakim; who, having reigned three months, was taken prisoner in 3405, and was carried to Babylon, with a great number of the Jewish nobility. The third captivity took place under Zedekiah, A. M. 3416. And thus, says Calmet, Matthew 1:11 should be read: Josias begat Joakim and his brethren: and Joakim begat Jechonias about the time of the first Babylonish captivity; and Jechonias begat Salathiel, after they were brought to Babylon. Thus, with the necessary addition of Joakim, the three classes, each containing fourteen generations, are complete. And to make this the more evident, I shall set down each of these three generations in a separate column, with the additional Joakim, that the reader may have them all at one view.
1 Abraham 1 Solomon 1 Jechonias 2 Isaac 2 Rehoboam 2 Salathiel 3 Jacob 3 Abia 3 Zorobabel 4 Judah 4 Asa 4 Abiud 5 Pharez 5 Josaphat 5 Eliakim 6 Esrom 6 Joram 6 Azor 7 Aram 7 Ozias 7 Sadoc 8 Aminadab 8 Joatham 8 Achim 9 Naason 9 Achaz 9 Eliud 10 Salmon 10 Ezekias 10 Eleazar 11 Booz 11 Manasses 11 Matthan 12 Obed 12 Amon 12 Jacob 13 Jesse 13 Josias 13 Joseph 14 david 14 joachim 14 jesus
In all forty-two generations.

and Josias begat (d) Jechonias and his brethren, at the time of the carrying away of Babylon.
(d) That is, the captivity fell in the days of Jakim and Jechonias: for Jechonias was born before the carrying away into captivity.

And Josias begat Jechonias,.... This Jechonias is the same with Jehoiakim, the son of Josias, called so by Pharaohnecho, when he made him king, whose name before was Eliakim, 2-Kings 23:34 begat of Zebudah, the daughter of Pedaiah of Rumah, 2-Kings 23:36.
and his brethren. These were Johanan, Zedekiah, and Shallum. Two of them were kings, one reigned before him, viz. Shallum, who is called Jehoahaz, 2-Kings 23:30 compared with Jeremiah 22:11, the other, viz. Zedekiah, called before Mattaniah, reigned after his son Jehoiakim: these being both kings, is the reason why his brethren are mentioned; as well as to distinguish him from Jechonias in the next verse; who does not appear to have had any brethren: these were
about the time they were carried away to Babylon, which is not to be connected with the word "begat": for Josiah did not beget Jeconiah and his brethren at that time, for he had been dead some years before; nor with Jechonias, for he never was carried away into Babylon, but died in Judea, and slept with his fathers, 2-Kings 24:6 but with the phrase "his brethren": and may be rendered thus, supposing understood, "which were at", or "about the carrying away to Babylon", or the Babylonish captivity.

And Josias begat Jechonias and his brethren--Jeconiah was Josiah's grandson, being the son of Jehoiakim, Josiah's second son (1-Chronicles 3:15); but Jehoiakim might well be sunk in such a catalogue, being a mere puppet in the hands of the king of Egypt (2-Chronicles 36:4). The "brethren" of Jechonias here evidently mean his uncles--the chief of whom, Mattaniah or Zedekiah, who came to the throne (2-Kings 24:17), is, in 2-Chronicles 36:10, as well as here, called "his brother."
about the time they were carried away to Babylon--literally, "of their migration," for the Jews avoided the word "captivity" as too bitter a recollection, and our Evangelist studiously respects the national feeling.

The carrying away to Babylon. The great seventy years' captivity in Babylon, following the destruction of Jerusalem by Nebuchadnezzar.

Josiah begat Jeconiah - Mediately, Jehoiakim coming between. And his brethren - That is, his uncles. The Jews term all kinsmen brethren. About the time they were carried away - Which was a little after the birth of Jeconiah.