And after they were brought to Babylon, Jechonias begat Salathiel; and Salathiel begat Zorobabel;
This is the very same Zorobabel who was so many years earlier used to help lead the Jews out of Babylon to rebuild Jerusalem. Here the Word of God focuses on the fact that he was born after the captivity. That is an obvious fact, but is singled out for thought in Matthew.
Perhaps it is just to mark that this is when the captivity took place among the generations of Jesus. But I think there is another reason. I think God wanted us to remember that even during that terrible time, God was planning wonderful things. I doubt that Jechonias or Salathiel even dreamed that one of their own would be so instrumentally used of the Lord. Yet God was working things into the future.
The same is true in our lives. Sometimes, when we are going through terrible times, we have great trouble seeing how things could ever work out again. In those times of despair it is very important to lean upon the Lord Jesus Christ, let Him give you rest and peace and simply trust Him that He often turns terrible situations into wonderful results.