Then all the captains of the forces, and Johanan the son of Kareah, and Jezaniah the son of Hoshaiah, and all the people from the least even unto the greatest, came near, and said unto Jeremiah the prophet, “Let, we beseech thee, our supplication be accepted before thee, and pray for us unto the LORD thy God, even for all this remnant; (for we are left but a few of many, as thine eyes do behold us:) that the LORD thy God may shew us the way wherein we may walk, and the thing that we may do.”
Then Jeremiah the prophet said unto them, “I have heard you; behold, I will pray unto the LORD your God according to your words; and it shall come to pass, that whatsoever thing the LORD shall answer you, I will declare it unto you; I will keep nothing back from you.”
Then they said to Jeremiah, “The LORD be a true and faithful witness between us, if we do not even according to all things for the which the LORD thy God shall send thee to us. Whether it be good, or whether it be evil, we will obey the voice of the LORD our God, to whom we send thee; that it may be well with us, when we obey the voice of the LORD our God…”                          Jeremiah 42:1-6

Be sure to read the rest of the chapter, and chapter 43.