The difference between sanad and isnād

Some ḥadīth scholars have said that isnād is a synonym of sanad.¹ But others have rejected this synonymy outright and insist that these two terms are different. Isnād, according to them, is the ascription of a ḥadīth to the one who said it and is thus a means of attaining information about the chain of transmission, whereas the sanad it the chain of transmission itself.²

The latter view is supported by a ḥadīth from Amīr al-Muʾminīn (‘a) where the term isnād has been used:

إِذَا حَدَّثْتُمْ بِحَدِيثٍ فَأَسْنِدُوهُ‏ إِلَى الَّذِي حَدَّثَكُمْ فَإِنْ كَانَ حَقّاً فَلَكُمْ وَ إِنْ كَانَ كَذِباً فَعَلَيْهِ

When you narrate a ḥadīth, ascribe it to the one who narrated it to you; for if it is true then you will gain [the reward] and if it is a lie, he will be responsible.³

Based on this difference between isnād and sanad, those who define sanad as being information about the chain of transmission have erred⁴ because this is the definition of isnād, not sanad.⁵

Notes:

1. See: Mīrdāmād, al-Rawāshiḥ al-Samāwiyyah, p. 126

2. See: Māmqānī, Miqbās al-Hidāyah, vol. 1, p. 52

3. Kulaynī, al-Kāfī, vol. 1, p. 52

4. Suyūṭī, Tadrīb al-Rāwī, vol. 1, p. 22

5. See: Māmqānī, Miqbās al-Hidāyah, vol. 1, pp. 51-52