Gantz, who tweeted it was a "night of great hope," headed to Washington for pre-scheduled talks Thursday on Iran with US officials including Secretary of State Antony Blinken.
Critics have accused Bennett of betraying his nationalist voters as he pursues a unity government with dovish Meretz and with support from the Arab Israeli Islamic conservative party Raam.
A statement from Israeli Prime Minister Benjamin Netanyahu's office said the security cabinet had "unanimously accepted the recommendations to accept an Egyptian initiative for an unconditional... ceasefire."