Jeremiah (Yirmiyahu) Chapter 28 as translated by https://mechon-mamre.org/p/pt/pt1128.htm
1 And it came to pass the same year, in the beginning of the reign of Zedekiah king of Judah, in the fourth year, in the fifth month, that Hananiah the son of Azzur the prophet, who was of Gibeon, spoke unto me in the house of the LORD, in the presence of the priests and of all the people, saying:
2 ‘Thus speaketh the LORD of hosts, the God of Israel, saying: I have broken the yoke of the king of Babylon.
3 Within two full years will I bring back into this place all the vessels of the LORD’S house, that Nebuchadnezzar king of Babylon took away from this place, and carried them to Babylon;
4 and I will bring back to this place Jeconiah the son of Jehoiakim, king of Judah, with all the captives of Judah, that went to Babylon, saith the LORD; for I will break the yoke of the king of Babylon.’
5 Then the prophet Jeremiah said unto the prophet Hananiah in the presence of the priests, and in the presence of all the people that stood in the house of the LORD,
6 even the prophet Jeremiah said: ‘Amen! the LORD do so! the LORD perform thy words which thou hast prophesied, to bring back the vessels of the LORD’S house, and all them that are carried away captive, from Babylon unto this place!
7 Nevertheless hear thou now this word that I speak in thine ears, and in the ears of all the people:
8 The prophets that have been before me and before thee of old prophesied against many countries, and against great kingdoms, of war, and of evil, and of pestilence.
9 The prophet that prophesieth of peace, when the word of the prophet shall come to pass, then shall the prophet be known, that the LORD hath truly sent him.’
10 Then Hananiah the prophet took the bar from off the prophet Jeremiah’s neck, and broke it.
11 And Hananiah spoke in the presence of all the people, saying: ‘Thus saith the LORD: Even so will I break the yoke of Nebuchadnezzar king of Babylon from off the neck of all the nations within two full years.’ And the prophet Jeremiah went his way.
12 Then the word of the LORD came unto Jeremiah, after that Hananiah the prophet had broken the bar from off the neck of the prophet Jeremiah, saying:
13 ‘Go, and tell Hananiah, saying: Thus saith the LORD: Thou hast broken the bars of wood; but thou shalt make in their stead bars of iron.
14 For thus saith the LORD of hosts, the God of Israel: I have put a yoke of iron upon the neck of all these nations, that they may serve Nebuchadnezzar king of Babylon; and they shall serve him; and I have given him the beasts of the field also.’
15 Then said the prophet Jeremiah unto Hananiah the prophet: ‘Hear now, Hananiah; the LORD hath not sent thee; but thou makest this people to trust in a lie.
16 ‘Therefore thus saith the LORD: Behold, I will send thee away from off the face of the earth; this year thou shalt die, because thou hast spoken perversion against the LORD.’
17 So Hananiah the prophet died the same year in the seventh month.
Why Did Jeremiah (Yirmiyahu) say Amen (See Verse 6) to the Predictions of the False Prophet?
The answer is that he probably had in mind the comment made by Rashi to verse 7 (translation from Sefaria.org)
But, hearken now… The prophet who would prophesy for peace. He said: I prophesy retribution. If it does not come, I am not a liar, for the Holy One, blessed be He, renounces the evil, but the prophet who prophesies for peace, etc., when the word of the prophet comes, etc., but if his word does not come, he is a liar, as it is said, “God is not a man that He should lie, etc.” (Num. 23:19). In this manner Rabbi Tanhuma (Vayera 13) expounded.
Nevertheless, Jeremiah’s (Yirmiyahu’s) False Flattery to a False Prophet Had Negative Side Effects
Moreh Tzedek whose view appears in Rashi’s commentary to verse 6 stated that whoever flatters a wicked man will ultimately fall into his hands or into the hands of his son or into the hands of his son’s son, for Irijah, the son of Shelemiah, the son of Hananiah seized Jeremiah and brought him to prison.
And Rabbeinu Bachayei similarly says in his book, Kad Hakemach on Flattery
That our sages in Sotah (chapter 7) stated: All that flatter the wicked in the end fall in his hand; and if he doesn’t fall into his hand he falls into the hand of his son or into the hand of his grandson for it was stated (Jeremiah chapter 28 verse 6) even the prophet Jeremiah said: ‘Amen! the LORD do so!
Jeremiah (Yirmiyahu) was issuing a prophesy that the remaining Temple vessels would be brought to Babylon and remain there while Hananiah issued a prophesy that the Temple vessels already taken by Nebuchadnezzar (Nevuchadnetzar) would return within two years and all the more so, that he would not take the remaining vessels and Jeremiah knew that Hananiah was speaking falsely but flattered him and did not try to make him retract his words and said ‘Amen! the LORD do so! and in the end fell in the hand of Irijah, the son of Shelemiah, the son of Hananiah; for it was stated (in Jeremiah chapter 37:13) “and he laid hold on Jeremiah”.
More Background On How Jeremiah Was Sent to Prison – Jeremiah Chapter 37
1 And Zedekiah the son of Josiah reigned as king, instead of Coniah the son of Jehoiakim, whom Nebuchadrezzar king of Babylon made king in the land of Judah.
2 But neither he, nor his servants, nor the people of the land, did hearken unto the words of the LORD, which He spoke by the prophet Jeremiah.
3 And Zedekiah the king sent Jehucal the son of Shelemiah, and Zephaniah the son of Maaseiah the priest, to the prophet Jeremiah, saying: ‘Pray now unto the LORD our God for us.’
4 Now Jeremiah came in and went out among the people; for they had not put him into prison.
5 And Pharaoh’s army was come forth out of Egypt; and when the Chaldeans that besieged Jerusalem heard tidings of them, they broke up from Jerusalem.
6 Then came the word of the LORD unto the prophet Jeremiah, saying:
7 ‘Thus saith the LORD, the God of Israel: Thus shall ye say to the king of Judah, that sent you unto Me to inquire of Me: Behold, Pharaoh’s army, which is come forth to help you, shall return to Egypt into their own land.
8 And the Chaldeans shall return, and fight against this city; and they shall take it, and burn it with fire.
9 Thus saith the LORD: Deceive not yourselves, saying: The Chaldeans shall surely depart from us; for they shall not depart.
10 For though ye had smitten the whole army of the Chaldeans that fight against you, and there remained but wounded men among them, yet would they rise up every man in his tent, and burn this city with fire.’
11 And it came to pass, that when the army of the Chaldeans was broken up from Jerusalem for fear of Pharaoh’s army,
Jeremiah Goes To Prison on Account of the Grandson of the False Prophet
12 then Jeremiah went forth out of Jerusalem to go into the land of Benjamin, to receive his portion there, in the midst of the people.
13 And when he was in the gate of Benjamin, a captain of the ward was there, whose name was Irijah, the son of Shelemiah, the son of Hananiah; and he laid hold on Jeremiah the prophet, saying: ‘Thou fallest away to the Chaldeans.’
14 Then said Jeremiah: ‘It is false; I fall not away to the Chaldeans’; but he hearkened not to him; so Irijah laid hold on Jeremiah, and brought him to the princes.
15 And the princes were wroth with Jeremiah, and smote him, and put him in prison in the house of Jonathan the scribe; for they had made that the prison.
16 When Jeremiah was come into the dungeon-house, and into the cells, and Jeremiah had remained there many days;
17 then Zedekiah the king sent, and fetched him; and the king asked him secretly in his house, and said: ‘Is there any word from the LORD?’ And Jeremiah said: ‘There is.’ He said also: ‘Thou shalt be delivered into the hand of the king of Babylon.’
Jeremiah Speaks Now Against the False Prophets and His Situation Improves
18 Moreover Jeremiah said unto king Zedekiah: ‘Wherein have I sinned against thee, or against thy servants, or against this people, that ye have put me in prison?
19 Where now are your prophets that prophesied unto you, saying: The king of Babylon shall not come against you, nor against this land?
20 And now hear, I pray thee, O my lord the king: let my supplication, I pray thee, be presented before thee; that thou cause me not to return to the house of Jonathan the scribe, lest I die there.’
21 Then Zedekiah the king commanded, and they committed Jeremiah into the court of the guard, and they gave him daily a loaf of bread out of the bakers’ street, until all the bread in the city was spent. Thus Jeremiah remained in the court of the guard.
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