He always remembered the advice his father gave him on his deathbed.
Tips
usage
叮咛 is gentler and more literary than 叮嘱 or 嘱咐, typically a parent's caring reminders. 千叮咛万嘱咐 means "to tell someone over and over". It is also written 丁宁, the same characters as the name of the table-tennis champion 丁宁.