I have memorized two kinds of knowledge from Allah's Messenger (ﷺ) . I have propagated one of them to you and if I propagated the second, then my pharynx (throat) would be cut (i.e. killed).
Sahih al-Bukhari Book 3, Hadith 62
← Previous Hadith I said to Allah's Messenger (ﷺ) "I hear many narrations (Hadiths) from you but I forget them." Allah's Apostle said, "Spread your Rida' (garment)." I did accordingly and then he moved his hands as if filling them with something (and emptied them in my Rida') and then said, "Take and wrap this sheet over your body." I did it and after that I never forgot any thing. Narrated Ibrahim bin Al-Mundhir:

Ibn Abi Fudaik narrated the same as above (Hadith...119) but added that the Prophet (ﷺ) had moved his hands as if filling them with something and then he emptied them in the Rida' of Abu Huraira.

Sahih al-Bukhari Book 3, Hadith 61 Next Hadith → The Prophet (ﷺ) said to me during Hajjat-al-Wida`: Let the people keep quiet and listen. Then he said (addressing the people), "Do not (become infidels) revert to disbelief after me by striking the necks (cutting the throats) of one another (killing each other).

Sahih al-Bukhari Book 3, Hadith 63