Human effort and Divine grace are needed to achieve success in any endeavor. Though butter is present in the milk, one cannot see it, unless one makes it into curd and churns it. Likewise, though Divinity is all-pervasive, one cannot experience it unless one makes appropriate efforts. Human effort can be compared to the process of churning.
(From : Sai Veda, The Word of God, sayings of Bhagavan Sri Sathya Sai Baba)