Musnad Ahmad 6:9

Muhammad ibn Ubayd narrated to us, Muhammad ibn Ishaq narrated to us, from Muhammad ibn Ibrahim, from Abu Salamah, who said: Two men from the people of Yemen stayed with Talhah ibn Ubayd Allah. One of them was killed alongside the Messenger of Allah (peace be upon him), then the other remained after him for a year, then he died in his bed. Talhah ibn Ubayd Allah was shown in a vision that the one who died in his bed entered Paradise before the other by a while. Talhah mentioned that to the Messenger of Allah (peace be upon him). The Messenger of Allah (peace be upon him) said: "How long did he remain after him?" He said: "A year." The Messenger of Allah (peace be upon him) said: "He prayed one thousand eight hundred prayers, and he fasted Ramadan."