You will remember that David had several wives – and Solomon had multitudes more. More kings and wives followed until there were a lot of people of the royal house. Among them was Nethaniah who, other than being the father of Ishmael, is unmentioned in the Bible.
Not everyone was deported to Babylon. Some of the poorest sort of people were left, but they would have to be cared for and that would require a leader. Nebuchadnezzar found one in Gedaliah, son of Jeremiah’s friend and protector (Jeremiah 39:14; 40:5-16 and 41:1-18).
Gedeliah urged the people who remained to settle down and get to work. Crops had to be harvested. Repairs had to be made. Defenses against marauders had to be built. But Ishmael resented Gedaliah’s leadership and assassinated him.
Now, Israel was defenseless and afraid. When news of Gedaliah’s death reached him, he would undoubtedly see the remnants in the land as rebellious and come to crush them. The plan was laid to escape to Egypt.
Israel came to Jeremiah for direction. The direction was not whether to go to Egypt, but direction about what they should do along the way or once they got there. When God told them not to do what they wanted to do, they did it anyway – and took Jeremiah with them.
The story in chapter forty-two is a great example of folks who want God’s direction as long as it affirms the course they’ve already set. When God, however, orders a course change, they are not so willing to hear Him.