How can one find God in the world of activity ?
You cannot easily detach yourself from activity. The mind clings to some thing or other. Make it cling to God. Let it do all things for God and leave the success or failure of things done to God, the loss and the profit, the elation or dejection. To get the attitude of surrender, of dedication, you must have faith in God. This world is a play; it is not an empty dream. It has a purpose and use. It is the means by which one can discover God. See Him in the beauty, the grandeur, the order, the majesty of Nature. These are but shadows of His Glory and His Splendor. That is why the Vedas have three section of Kaandas : Karma, Upasana and Jnana. Karma leads to consciousness of the ever-present, immanent, all-powerful God. Upasana or adoration of that God leads to the knowledge that He is in all; when you experience that there is no Second, that is Jnana! (SSS Vol 5, pg 105)