One of the hardest things to believe is that the nation and people of Israel will reunite. That they will be able to dismiss differences.
Disbelief aside, stands God’s promise to give all his people one heart. A heart which exceeds all religious, traditions, secular or politics differences which divide his people:
And I will give them a single heart and one direction, so they fear me all their lives for their own good and welfare of their children after them. (Jeremiah 32, 39)
However, I will send you Elijah the prophet before the great and dreadful day of the Lord arrives! And he shall turn the heart of the fathers to their children, and the heart of children to their fathers, lest I come and entirely sanctify the land with blow. (Malachi 3: 23-24)
I will make them a united nation in the country, the mountains of Israel, one king shall be the king of them all, and they shall not be any longer as two nations and never again split into two kingdoms. (Ezekiel 37, 22)