Answered by Shaykh Ilyas Patel
What are the limits of crossing the row (saff) in front of someone praying I recently crossed the saff but was well clear of where the person bows their head in sajda, I was told I had sinned for it, can you clarify this position as to where it is permissible to cross
when someone is paying?

There are many different opinions regarding the limits of crossing the saff in front of someone praying. They are as follows:
- If the person praying, during standing, looks at his place of prostration and as far as he can see, will be severely offensive (Makruh Tahriman) to cross for anyone.
- Some have are of the opinion of two or three rows
- Some have are of the opinion three hands length
(Umdatul’ Fiqh pg 374)
- Small mosques, houses and rooms which are not very big; less than 40 dhira, (1 Dhira = 48 centimetres x 40) then it would be severely offensive (Makruh Tahrim) to cross and pass until the qibla (direction of Ka’ba) of the wall, because this is considered as one place.
(Ibn Abidin, Hashiya Ibn Abidin V.1 pg 638& Umdatul’ Fiqh pg 374)