Hakim al Ummah Mawlana Ashraf Ali Thanawi (Allah have mercy on him) said,

‘This is the action that stops the random thoughts and whisperings (wasawes). It keeps the lower self (nafs) involved in something (beneficial). If it was to be left on its own it would get into something (spiritually) detrimental.

It is acknowledged that this action is the remembrance (of Allah) by heart (dhikr e qalbi).

This can be done at all the times.

Therefore, involve your nafs in this action. By doing so it will not get into detrimental things and heedlessness (gaflah).’

Jawahirat e Hakim al Ummat ra, volume 3, page 68