Al-Kāfi - Volume 6 > Clipping or Pulling out Gray Hairs
Hadith #6

عِدَّةٌ مِنْ أَصْحَابِنَا عَنْ أَحْمَدَ بْنِ أَبِي عَبْدِ اللَّهِ عَنْ أَبِي أَيُّوبَ الْمَدِينِيِّ عَنْ سُلَيْمَانَ الْجَعْفَرِيِّ عَنِ الرِّضَا عَنْ آبَائِهِ ( عليهم السلام ) قَالَ الشَّيْبُ فِي مُقَدَّمِ الرَّأْسِ يُمْنٌ وَ فِي الْعَارِضَيْنِ سَخَاءٌ وَ فِي الذَّوَائِبِ شَجَاعَةٌ وَ فِي الْقَفَا شُؤْمٌ .

6. A number of our people have narrated from Ahmad ibn abu ‘Abd Allah fn abu Ayyub al-Madiniy from Sulayman al-Ja‘fariy who has said the following: “Al-Rida’, ‘Alayhi al-Salam, has narrated from his ancestors saying, ‘Gray in front of the head is good fortune, on the sides is generosity, on top of the head is courage, and at the back is misfortune.’”