Answered by Shaykh Sohail Hanif, SunniPath Academy Teacher
2 people are praying salah. One is an Imaam and the other a follower. A 3rd person comes in and taps the shoulder or takes hold of the arm of the other follower. What exactly should be done in this case? Should the follower walk backwards as in normal walking or should he drag his feet backwards?
Assalamu alaykum
Excessive movement invalidates the prayer. Excessive movement is defined as that which if observed by an onlooker from afar he would be certain that one is not praying.
Any movement less than this will not affect the prayer unless it is repeated unnecessarily in which case it might count as abath (playing) which is prohibitively disliked (makruh tahriman).
Walking therefore will not invalidate the prayer as long as it is such that it does not look like the person is strolling. This is why the scholars recommend that someone who needs to walk during his prayer, to fill in a gap in a row for example, should take a step then pause and then take a second step and so on. Of course one must also be sure to keep facing the qibla whilst walking; to intentionally turn away from the direction of the qibla, the direction being 45 degrees on either side of it, would instantly render ones prayer invalid.
In al-Durr al-Mukhtar Imam al-Haskafi mentions the scenario where one walks towards the qibla the length of a prayer row (about one metre) then pauses for the length of a ruku (i.e. the time it takes to say subhana rabi al-adhim three times) then walks forward the length of a row then pauses the length of a ruku and so on. In this case the prayer is not invalid no matter how far one walks so long as one stays in the same place, i.e. the mosque or the room one is praying in. One can not, for example, walk to the suq whilst praying! [al-Durr al-Mukhtar, 1:421, (published with Radd al-Muhtar) Dar Li Ihya al-Turath al-Arabi]
There is no need to drag one’s feet whilst walking as long as one observe the way of walking described above.
And Allah knows best.