Answered by Ustadh Tabraze Azam
Question: Assalam alaykum,
Is it true that your prayer will not be accepted for 40 days if you have smoked weed?
Answer: Assalamu alaikum wa rahmatullahi wa barakatuh,
I pray that you are in the best of health and faith, insha’Allah.
Yes, the scholars mention that the reward of those prayers is not granted unless the person sincerely repents. [see: Drinking Alcohol: Are My Prayers Not Valid for 40 Days?]
In any case, it is not permitted to smoke marijuana. [see: Smoking Marijuana and the Importance of Keeping Good Company]
And please see: A Reader on Tawba (Repentance)
And Allah alone gives success.
Checked & Approved by Shaykh Faraz Rabbani.