Shaykh Yasir Qadhi contemplates on the verse below. The context of this verse is when the Muslims first heard of the Battle of Badr and they heard the enemy army approaching for which they were unprepared.
They said,
"Sufficient for us is Allah, and [He is] the best Disposer of affairs."
[Surah Ale Imran, 3:173]
The verse has also been recited in other places in the Qur'an.
"If only they had been satisfied with what Allah and His Messenger gave them and said, "Sufficient for us is Allah ; Allah will give us of His bounty, and [so will] His Messenger; indeed, we are desirous toward Allah," [it would have been better for them]."
[Surah Tawbah, 9:59]
This dua is not a dua so much so as it is a statement. The reason why this verse is so powerful is that the request is included in the statement and we present it as firm Iman. it is an affirmation of one’s Iman and that is sufficient to obtain Allah’s Rahmah and Mercy.