Virtues of Kalimah Tayyabah :

Hadith No.2 

That 'La Ilaha Illallah' is the best of all azkaar is quit evident. It is describes as such in many ahadith. In fact when the whole of Deen depends on this Kalimah Tauheed, there can hardly be any doubt that it is the highest of all azkaar. Again 'Al Hamdu Lillah' has been regarded as the best du'aa, because praising one who is the most benevolent person is in fact a form of begging. It is common ecperience that by writing a eulogy in praise of a man of wealth or of authority doest not mean anything else than begging his favours or riches.

Hadhrat Ibn Abbas (Radhiyallaho anho) says that one who recites 'Alhamdu Lillah' should follow it by 'La Ilaha Illallah' because in the Holy Qur'an the verse.

"Fad uhu mukhlisina lahud-din"

(Ask Allah with sincere devotion)

is followed by 'Al Hamdu Lillahe Rabbil Aalamin' (All praise is for Allah who is the Cherisher of all the universe).

Mulla Ali Qari (Rahmatullah alaih) has stated : "There is not slightest doubt that Kalimah Tayyibah is by far the best and foremost of all azkar because it is the root and fundamental basis of the Deen and the whole religion of Islam centers round it. It is for this reason that the Sufis and saints emphasis its importance and prefer it over all other azkaar and advise their followers to practice it as much as possible. Also, actual experience has shown that, the benefits following from Kalimah Tayyibah far outnumber those which  result from other forms of zikr.

There is a well-known story of Sayyid Ali bin Maymoon Meghrabi. Once Shaikh Ulwan Hamawi, who himself was a great scholar, Mufti and teacher of his age, came for learning zikr.The Sayyid (Rahmatullah alaih) devoted special attention to him and made him give up all his routines, as such as teaching and writing fatawa, and to take up zikr all the time. On this, the common people started freely indulging in fault finding and condemnation. They started a campaign of critism that the Shaikh has now been lost to them and the people were being deprived of is benefits. A few days later, when the Sayyid (Rahmatullah alaih) came to know that Shaikh Ulwan was occasionally reciting the Holy Qur'an, he stopped him from this recitation also. At this, the people lost all sense and openly accused the Sayyid, (Rahmatullah alaih), of irreligiousness and perversion. After some time, when the Shaikh observed that the zikr has had its effect on his heart, the Sayyid (Rahmatullah alaih) allowed him to resume recitation of the Holy Qur'an. When he opened the Book, every word and aayat emerged with new meanings and significance he never thought of before. The Sayyid (Rahmatullah alaih) then told Shaikh Hamawi that he had not forbidden him from recitation, but in fact he had desired to develop in him spiritual awareness, which was a pre-requisite for this recitation of the Qur'an.

As this Holy Kalimah constitutes the fundamental basis of religion and the rood of Imaan (faith), the greater the devotion to this Kalimah, the more firmly will Imann be rooted. Imaan depends on this Kalimah, and the very existence of this world depends on it. According to a hadith, the Day of Judgment will not dawn as long as there exists on Earth a single man reciting the Kalimah 'La Ilaha Illallah.' This is reported in other ahadith also. So long as there lives a single man on Earth who remembers Almighty Allah, Qiyaamat (Doomsday) will not take place.