Abu Hamid al Ghazaali’s advice when he was dying.
Ibn Kathir said:
وقد سأله بعض أصحابه وهو في السياق فقال: أوصني.
فقال: عليك بالإخلاص، ولم يزل يكررها حتى مات، رحمه الله.
Some of his companion asked him, advice me. While he (al Ghazaali) was in state of agonies of death:
He said: stick to sincerity/Honesty, and he kept repeating it until he died, may Allah have mercy on him.
al Bidaya wal Nihaya the year 505 h.