Malachi - the twelfth and final in the traditional listing by CHAZAL of the group of Prophets known as the "Trei-Asar," the "Twelve."

Malachi prophesied after the Temple had already been rebuilt, after its destruction by the Babylonians. By that time, the attitude of the Jews towards the Temple, and spiritual matters in general, had become apathetic. Furthermore, they had adopted many practices alien to the Spirit of the Torah.

Malachi portrays a debate between G-d and the People of Israel. The debate begins with G-d speaking first,

"I have loved you, says HaShem,
But you said, 'How have You loved us?'
Was not Esav the brother of Yaakov, says HaShem,
And I loved Yaakov!"
But I hated Esav,
And made his mountains a desolation,
And gave his inheritance to the jackals of the wilderness."
(Malachi 2-3)

HaShem accuses the People of not showing Him proper honor, of bringing Him blind and lame sacrifices, of not even measuring up to the nations in fear of the L-rd! And the People have no response.

He accuses them of not being loyal to their wives,

"…Because the L-rd has been witness
Between you and the wife of your youth,
Against whom you have acted treacherously,
Though she is your companion,
And the wife of your covenant."
(Malachi 2:14)

HaShem declares that they have not observed the Laws of "Maaser," that require donation of one tenth of one's produce to the Levi, and proposes a test of His faithfulness and capability:

"Bring the whole tithe into the storehouse,
That there may be food in my house
And test me, says HaShem,
If I will not open the windows of Heaven,
And pour you out a blessing,
That shall be far more than sufficient."
(Malachi 3:10)

Malachi challenges the People to return to G-d "before the coming of the great and terrible day of the L-rd!"

"Behold, I will send you
Eliyahu the Prophet,
Before the coming of the great and terrible
Day of the L-rd."

"And he shall turn the heart of the fathers to the children,
And the heart of the children to the fathers…"
(Malach 3:23-24)

After Malachi, the Talmud records that the gift of Prophecy was given to (holy) fools and madmen!

According to the RAMBAM, Malachi was a link in the Chain of "Mesorah," and received the Tradition of Torah from Baruch ben Neriah and his court.