It is related that a man asked the Prophet (s), “God’s Messenger, I am treating my aged parents as same as their treatment to me when I was child. Have I now performed their rights that are imposed upon me?” The Prophet (s) answered: “No, you have not, b ecause, when they treated you kindly during your childhood, they wanted you to live. But, now, while you are treating them kindly, you wish they would die.”
Ibrahim ibn Shuaib narrated: I told Imam as-Sadiq (a) that I used to carry my aged and weak father when he wanted to relieve nature. The Imam commented: “If you can do more than this, you must do it. You should feed him bit by bit, because he will guard you (from Hell) in the morrow.” (al-Wafi; part 3 page 92 (as quoted from al-Kafi)