Reward of reciting 'La ilaaha illallah' a hundred times

1. Imam Jafar as-Sadiq (a.s) says, "The deed of one who recites 'La illaaha illallah' a hundred times is better than all except one who recites it more than a hundred times."
2. Imam Jafar as-Sadiq (a.s) says, "Allah builds a house in paradise for one who recites 'La illaaha illallah' a hundred times before going to bed. And the sins of one who recites Astagfirullah a hundred times before going to bed are destroyed in the same way as dry leaves fall off from a tree.

Ref: Sawaabul Aamaal and Iqaabul Aamaal