Reciting منها خلقناكم when throwing sand in the grave

Q: Is there any authentic hadith from the books of hadith about: When throwing the first handful one should say, "Of this (i.e. the earth) We created you," and on the second one should say, "And to it shall We cause you to return," and on the third handful one should say, "And of it We shall cause you to be resurrected a second time. Please give me the references.

Is it kufr to say that a certain medicine cures

Q: Is it kufr to say that this medicine cures like acne as example. Like is it kufr to put your trust in that medicine? Before I read a fatwa of someone asking that question but they said its not, I don't really remember. But now I am hearing that Allah cures him not the medicine, so I am confused. So whenever I say this medicine has a cure for this, I think is the cure from Allah or Allah put the cure in the medicine. But I know if Allah wills he wouldn't let him be cured by that medicine. Did I commit kufr?

Hazrat Muawiyah (Radhiyallahu Anhu)

Q: I have some questions regarding Hazrat Muawiyah (Radhiyallahu Anhu). 

  1. Was he one of the scribes who wrote down the Qur'an or simply one of the scribes who dictated Nabi sallallahu alayhi wa salam's letters to other rulers?
  2. Is it true that there is a hadeeth in Saheeh Bukhari narrating how Nabi (Sallallahu Alayhi Wasalam) explicitly cursed him?
  3. Are there also hadeeths narrating how Muawiyah (Radhiyallahu Anhu) will be denied water from Nabi (Sallahu Alayhi Wasalam's) hands at Al-Kawthar and how Nabi (Sallallahu Alayhi Wasalam) cursed him because he (Radhiyallahu Anhu) kept on eating eating while Nabi (Sallallahu Alayhi Wasalam) was summoning him?
  4. Was his sister one of the Ummul Mu'mineen (Radhiyallahu anhum)? Did Nabi (Sallallahu Alayhi Wasalam) make dua that he would be a great king?