Abu Abdir-Rahmaan Al-Asadiy (rahimahullaah) said: I said to Saeed Ibn Abdil Azeez (rahimahullaah): O father of Muhammad! What is this weeping that occurs from you in salaah? He said: O son of my brother! What is the (reason) for your question about this? I said: O my uncle! Perhaps Allaah may benefit me by it.  So Saeed said: I do not stand up in my salaah except that the hell fire is exemplified for me. 

Abu Mushir (rahimahullaah) said: A man said to Saeed Ibn Abdil Azeez (rahimahullaah): May Allaah prolong your life; so he became angry and said: ”rather may Allaah hasten His mercy for me.”

[Source: Seeratus Salaf As-Saaleh by: Imaam Ismaaeel Bin Muhammad Bin Fadl Al-Asbahaanee (535AH: Chapter: A mention of those who followed the companions in righteousness]