John and Doves,
Ezekiel 4:4 Lie thou also upon thy left side, and lay the iniquity of the house of Israel upon it: according to the number of the days that thou shalt lie upon it thou shalt bear their iniquity. 5 For I have laid upon thee the years of their iniquity, according to the number of the days, three hundred and ninety days: so shalt thou bear the iniquity of the house of Israel. 6 And when thou hast accomplished them, lie again on thy right side, and thou shalt bear the iniquity of the house of Judah forty days: I have appointed thee each day for a year.
God tells Ezekiel to lie on his left side for 390 days, and then right side for 40 days. Each day represents a year. This command was given forth on Tammuz 12 in 593 BC, 7 years before destruction of Judah in 586 BC. Here's a calculation. When we add 430 days ( 390 + 40) to Tammuz 12, we come to Elul 29 which is the evening of Rosh Hashana. On the evening of Rosh Hashana, Ezekiel finished lying on his left and right side for 430 days. Judgment on the house of Israel shall begin. Simply put, on a future Rosh Hashana, God shall begin His judgment on the house of Israel and Judah.
From my calculation of 430 years iniquity of Israel and Judah, I have Rosh Hashana 2025 as the beginning of Jacob's trouble. Now we should know why God picked Tammuz 12 to give Ezekiel the 430 days equal to years prophecy. It is because He wants us to know that time of Jacob's trouble shall begin on a future Rosh Hashana.
Tammuz 12 + 430 days = Elul 29