Ibn 'Abbas (May Allah be pleased with them) said:
When (Prophet) Ibrahim (Abraham) was thrown into the fire, he said: "Allah (Alone) is sufficient for us, and, He is the Best Disposer of affairs." So did Messenger of Allah Muhammad (ﷺ) when he was told: "A great army of the pagans had gathered against him, so fear them". But this (warning) only increased him and the Muslims in Faith and they said: "Allah (Alone) is sufficient for us, and He is the Best Disposer of affairs (for us)".[Al-Bukhari].
Arabic/English book reference: Book 1, Hadith 76