Jeremiah 40-42

In Jeremiah 42 we read about the leaders of Judah's remnant asking God's prophet for the LORD's direction. They fear the response of the king of Babylon for the assassination of his governor; an act they did not commit or approve. In the first six verses we see the detail of their request. Jeremiah did pray to God for guidance but verse 7 tells us that God waited 10 days before he returned an answer. Why did God wait so long? To the leader's credit they waited for God's answer. But when they received an answer with which they disagreed they rejected it. Why would they wait on God only to reject his leading? I'm not sure which is the greater message for Christians. We must be willing to wait and keep praying. But we also must heed God's answer when he does speak.
Stuart