الحفيظ
الحفظُ في اللغة هو مراعاةُ الشيء، والاعتناءُ به، و(الحفيظ) اسمٌ...
Sālim ibn ‘Abdullāh ibn ‘Umar ibn al-Khattāb (may Allah be pleased with him) reported from his father that the Messenger of Allah (may Allah's peace and blessings be upon him) said: "What an excellent man ‘Abdullāh is if only he observes the night prayer." Sālim said: "Since then, ‘Abdullāh would not sleep at night but very little."
The Prophet (may Allah's peace and blessings be upon him) said that ‘Abdullāh ibn ‘Umar was a righteous man and encouraged him to perform Qiyām. So, since then, he used to sleep very little at night.