Du'a using Allah's Name Al-Awwal Al-Akhir

اللَّهُمَّ يَا أَوَّلُ يَا آخِرُ أَنْتَ فِي الْكُلِّ حَسْبُنَا

Allahumma ya Awwalu ya Aakhiru anta fil kulli hasbuna

O Allah, The First and The Last, You are sufficient for us in everything.

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