It is narrated from Sayyiduna Sulayman bin Surad (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said on the day of (the Battle of) al-Ahzab: "Today we will attack them, and they will not attack us."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6455