Charles Ellicott Commentary Jeremiah 34:5

"thou shalt die in peace; and with the burnings of thy fathers, the former kings that were before thee, so shall they make a burning for thee; and they shall lament thee, [saying], Ah Lord! for I have spoken the word, saith Jehovah." — Jeremiah 34:5 (ASV)

And with the burnings of your fathers ... — Spices and perfumes were burnt as a mark of honour at the burial of kings and persons of high rank, and this is the burning here referred to (2 Chronicles 16:14; 2 Chronicles 21:19). The Hebrews never adopted the practice of burial by cremation, and for the most part embalmed their dead after the manner of Egypt (John 19:39–40).

They will lament you, saying, Ah lord! ... — The words derive their full effect from their contrast with the prediction which the prophet had uttered (Jeremiah 22:18) as to the burial of Jehoiakim without any of the usual honours of the funeral dirges of the mourners. Here he comforts Zedekiah with the thought that no such shameful end was in store for him, leaving the place where he was to die uncertain.