The following is from YOGA JOURNAL by Judith Lasater. I was pleased with what I read...
Isvara Pranidhana (Surrendering to God)
Patanjali defines "isvara" as "Lord," and the word "pranidhana" conveys the sense of "throwing down" or "giving up." Thus, isvara pranidhana can be translated as "giving up or surrendering the fruits of all our actions to God."
Many people are confused by this niyama, in part because yoga is seldom presented as a theistic philosophy even though Patanjali states in the 23rd verse of the Yoga Sutra that devotion to the Lord is one of the main avenues to enlightenment).
In fact, some yoga traditions have interpreted isvara pranidhana as requiring devotion to a particular deity or representation of God, while others have taken "isvara" to refer to a more abstract concept of the devine (much as Twelve Step programs allow participants to define "Higher Power" in their own way).
In either case, the essence of isvara pranidhana is acting as best we can, and then relinquishing all attachment to the outcome of our actions. Only by releasing our fears and hopes for the future can we really be in union with the present moment.
Paradoxically, this surrender requires tremendous strength. To surrender the fruits of our actions to God requires that we give up our egotistical illusion that we know best, and instead accept that the way life unfolds may be a part of a pattern too complex to understand. This surrender, however is anything but passive inactivity. Isvara pranidhana requires not just that we surrender, but also that we act.