Dhikr by Word and by Action,
 
from Shaykh Ahmad Sirhindi
 
There are many different ways of dhikr (remembrance of Allah), both through obeying Allah's Laws, and through repeating certain phrases. Shaykh Ahmad Sirhindi helps to clarify the relationship between the different ways of dhikr in the following passage. Shaykh Ahmad Sirhindi says: 
Remember that dhikr means to avoid forgetting Allah in any way that is possible. Contrary to what people think it is not confined to repeating the formula of nafi wa ithbat (i.e. la ilaha illa Allah) or repeating the ism dhat (i.e. Allah). In fact every act in compliance to the commands of Allah, whether positive or negative, is to remember Allah. Even the buying and selling in which you observe the regulations of the Shar` is dhikr; similarly, the marriage and divorce which is carried out according to the laws of the Shari`ah is dhikr. For one who performs these acts according to the Shar` is conscious of the Giver of the Shar` and does not forget Him. 

To be sure, the dhikr which consists in saying the names and attributes of Allah is more effective and more helpful in generating the love of Allah, and winning His nearness; and the dhikr which consists in submitting to Allah's commands, in carrying out His orders or abstaining from His prohibitions, is less effective in producing these qualities. However, some people have acqired these qualities as a result of practising dhikr in the sense of obeying Allah's commands and avoiding His prohibitions. But such cases are few. Khwajah Naqshband has said about Zain 'l-Din Tabyadi that he reached Allah by way of knowledge. 

On the other hand, the dhikr which is saying the names and attributes of Allah, is a means (wasilah) to the dhikr which is obeying the rules of the Shar` in life. For it is impossible to observe the rules of the Shar` in all matters unless one has a strong love for the Giver of the Shar`, and the strong love of Allah depends upon the dhikr of Allah by saying His names and attributes. Hence one has to say dhikr in order to do this noble dhikr.

[Quoted from "Sufism and Shari`ah: A study of Shaykh Ahmad Sirhindi's Effort to Reform Sufism," by Muhammad Abdul Haq Ansari (The Islamic Foundation, Leicester, UK, 1986), pp. 232-3. Originally from Shaykh Ahmad Sirhindi's letters, Vol. II:46. I have replaced the word "God" in the translation with the word "Allah".]