When Hazrat Abu Bakr (radhiyallahu ‘anhu) was in his final illness, he dictated the following letter to Hazrat ‘Uthmaan (radhiyallahu ‘anhu) in which he appointed Hazrat ‘Umar (radhiyallahu ‘anhu) as the Khalifah after him:

Bismillahir Rahmaanir Raheem

This is the instruction of Abu Bakr, the son of Abu Quhaafah, at the very end of his life in this world, while exiting the world and entering the life of the Hereafter, and he is close to reaching the point (of the throes of death, wherein the signs of the Hereafter become clear to a person and) where a kaafir will wish that he had brought Imaan, a sinner realizes and gains full conviction of his condition, and a liar will wish to become truthful.