The UN gave Israel a specified piece of land. Israel now occupied much more of the Palestinian mandate than the British gave them. They also have grabbed chunks of what was Lebanon and Syria and annexed it. Neither was allowed by the UN Charter.
I don't see how defeating Israel would benefit Iran much. Iran wants no part of Israel, Israel wants no part of Iran.
The Ayatollah of Iran blames Israel for sanctions. It uses Israel as a scapegoat to justify the poor economic situation of Iranians.
Neither side can win this.
Can an entire country "hate" another?