Quran demands zikre Katheer (plentiful zikr) from believers:
*"Ya ayyuhallazina amano zkurallaha zikran katheeran wa sabbehoohu bukaratn wa aseela"
*"Wazkurullaha katheeran lallakum tuflehoon"
*"Allazina yazkoroonallaha Qiyaman waa quoodan wa ala junoobehem"
and many similar ayaat and ahadeeth can be quoted.
One ayat in particular guides us more clearly:
"Rijalun la tulheehim tijaratun wa la baiun an zikrellah"
Allah swt specifically mentions those people who never forgets Allah.
It means that one should always remember Allah swt,that is an attribute of Qalb and not tongue,it also does not mean the "word" ALLAH to be more specific,rather it means remembering Allah,Yad dasht,permanent tawajjo ilaallah.If i ask you "ahmed please remeber me (or don,t forget me) it obviously does not mean that you sit in a corner of the house,take tasbeeh and recite my name daily for a long time,remembering is "yad". full stop. Just like you remember your children without names,every father and specially mother,seldom forget the children,they remember them even if they don't take their names.
A much better example would be the way we are always aware of our own self, all the time, with out any conscious effort. Any one who is not aware of self would be in coma or deep sleep.keeping this explaination in mind,now read this ayat,you will get new taste of it."La takoonu kallazina nasollaha fa ansahum anfosahum olaika humolfaseqoon"....."and be you not like those who forgot Allah:and HE made them forget their own souls !
So the purpose is Yad dasht,but can with this un prepared mind we reach this stage,obviously not,and there the Ziker of the NAME comes first.How to achieve purpetual, nonstop ziker(which remains continued,even if we are involved in wordly affairs apparently)?.Our mashaikh thought about it,and found that two systems in the body are sort of AUTOMATIC,ie heart beats non stop and breathing continues nonstop.They devised methods,therefore,to make ziker their constant quality,resulting in Zikre qalbi and pase anfas,but please remember pase anfas is not a goal in itself ,it is a tool towards the actual goal,which is:TO REMEMBER ALLAH IN ABSTRACT terms,not associated with words,features,body,colour, etc.
Controlling the thoughts is very important. In Irshaad ul Mulook it is mentioned over and over again. I think in there it is mentioned that a human gets 70,000 thoughts per day. Islam came to change our thinking too. I remember maulana Yunus patel saheb saying that when you get evil thoughts in your head about women etc then just imagine your infront of the kabah or infront of the raudah of Rasulullah sallahuwaslaam...etc etc...anyway ALLAH give us taufeeq.