The current Iranian leadership has made its' position exceptionally clear: no peace without the elimination of the state of Israel. The massive missile arsenal they have prepared is designed to devastate Israeli cities and military bases (especially air bases). These missiles needed to be smuggled in so the largest missiles are still relatively small in number. With this agreement Iran will be able to openly ship large numbers of their most deadly missiles, along with Revolutionary Guard troops to man them. If this occurs then Israel will have little choice but to preemptively strike or face certain annihilation under a Missile Apocalypse. The Doomsday clock for war has now reached its' last minute.
Rohani: Nuclear deal achieves Iran's goals (AP)
from the article: Iran offers to protect Lebanon and Hezbollah defense needs