Chapter on Disciplining and Testing a Child
Man Lā Yaḥḍuruh al-Faqīh|Volume 3|Book 3|Chapter 53
وَ فِي رِوَايَةِ حَمَّادِ بْنِ عِيسَى قَالَ: "يَشِبُّ اَلصَّبِيُّ كُلَّ سَنَةٍ أَرْبَعَ أَصَابِعَ بِإِصْبَعِ نَفْسِهِ".
In the narration of Hammad ibn Isa, it is reported: "A child grows every year by four finger-widths, measured by his own finger."
- Ṣaḥīḥ al-Faqīh