Answered by Ustadh Tabraze Azam
Question: Assalamu alaikum
After congregational prayers in the mosque, when people leave, it seems almost impossible to avoid passing in front of a person still doing prayers.
Is it a sin upon me every time I pass in front of a praying person?
Answer: Wa alaikum assalam wa rahmatullahi wa barakatuh,
I pray that you are in the best of health and faith, insha'Allah.
In general, it is sinful to walk immediately in front of [= i.e. across their place of prostration] somebody praying when it is easy to avoid.
The Holy Prophet (Allah bless him and give him peace) said, "If the person passing in front of a man praying knew what he was incurring, he would find it preferable to wait forty rather than pass in front of him." [Bukhari] A variant in Bazzar's Musnad says "forty years."
Some of the commentators have mentioned that that this would be considered from the major sins (kaba'ir). [see: Major vs Minor Sins, and Haram vs. Makruh Tahriman]
What if I have to pass in front of them?
However, the jurists state four cases, as Ibn `Abidin writes in his Hashiya:
(1) The one passing has an alternative, and the one praying is in the way of others: both are sinful.
(2) The one passing has an alternative, and the one praying is not in the way of others: the one passing is sinful.
(3) The one passing has no alternative, and the one praying is in the way of others: the one praying is sinful.
(4) The one passing has no alternative, and the one praying is not in the way of others: neither is sinful.
This is the reason why the scholars tend to recommend placing a barrier (sutra) in front of one when praying.
And Allah alone gives success.
Checked & Approved by Shaykh Faraz Rabbani.