Du'a using Allah's Name Al-Qawiyy

اللَّهُمَّ يَا قَوِيُّ قَوِّ عَزْمَنَا

Allahumma ya Qawiyyu qawwi 'azmana

O Allah, The All-Strong, strengthen our resolve.

A general supplication, not a narration from the Prophet (peace be upon him).