Matthew Henry Commentary Jeremiah 39:15-18

"Now the word of Jehovah came unto Jeremiah, while he was shut up in the court of the guard, saying, Go, and speak to Ebed-melech the Ethiopian, saying, Thus saith Jehovah of hosts, the God of Israel: Behold, I will bring my words upon this city for evil, and not for good; and they shall be accomplished before thee in that day. But I will deliver thee in that day, saith Jehovah; and thou shalt not be given into the hand of the men of whom thou art afraid. For I will surely save thee, and thou shalt not fall by the sword, but thy life shall be for a prey unto thee; because thou hast put thy trust in me, saith Jehovah." — Jeremiah 39:15-18 (ASV)

Here is a message to assure Ebed-melech of a recompense for his great kindness to Jeremiah. Because thou hast put thy trust in me, saith the Lord. God recompenses men's services according to their principles. Those who trust God in the way of duty, as this good man did, will find that their hope shall not fail in times of the greatest danger.