The Book Pertaining to Piety and Softening of Hearts (Kitab Al-Zuhd wa Al-Raqa'iq)
Muslim :: Book 42 : Hadith 7072
It is reported on the authority of Amir b. Sa'd that Sa'd b. Abi Waqqas was in the fold of his camels that his son 'Umar came to him. When Sa'd saw him he said: I seek refuge with Allah from the mischief of this rider. And as he got down he said to him: You are busy with your camels and your sheep and you have abandoned people who are contending with one another for kingdom. Sa'd struck his chest and said: Keep quite. I heard Allah's Messenger (may peace be upon him) as saying: Allah loves the servant who is God-conscious and is free from want and is hidden (from the view of people).