Sunan At-Tirmidhi

Narrated Ibn Ashwa:from Yazid bin Salamah Al-Ju'fi, he said: ""Yazid bin Salamah 'O Messenger of Allah! I heard so many narrations from you that I am afraid the last of them will cause me to forget the first of them. So narrate a statement to me that will encompass them.' So he said: 'Have Taqwa of Allah with what you learn