It is narrated by Abdullah ibn Sanaan who said: When Imam Sadeq (AS) commented on this part of Ayah 29 of Surah Al-Isra which says: “Do not tie your hand to your neck”; he clenched his fist tightly and said to us: Avoid this; which it is the extreme stinginess. And commenting on the other part of the same Ayah which says: “nor stretch it forth to its utmost reach”; he opened his fist completely and said: This is also not right; meaning, it is not appropriate for a person to spend whatever he/she has and nothing is left [1]. The conclusion is that, the above holy verse rejects going to extremes in life.
[1] Wasaelul Shia, Vol. 17, page 66.
source : Shafaqna