Musnad Ahmad 30:3538

Rawh narrated to us, Muhammad ibn Abi Hafsah narrated to us, Ibn Shihab narrated to us, from Abu Ubayd, the freed slave of Abd al-Rahman ibn Awf, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "None of you should wish for death; either he is an evildoer, so he may seek forgiveness, or he is a doer of good, so he may increase [in good deeds]."