Every action we are doing is sure to bring a fruit. Even though we may claim it to be a sacrifice to God (as per Karma Yoga), that fruit is sure to come back to us only, at some point of time, at some context, at some quantity and fashion. How and when cannot be exactly comprehended by us, because God is definitely going to give it back to us as per His will, with our welfare in mind. God is beyond needs and wants and He is not looking to retain the fruits of OUR labor with Himself!
My Guru Mata Amritanandamayi (Amma) use to say that when Bhagavad Gita says work should be done by surrendering the results to God, it means we don’t have to break our head or worry about the fruits of Karma, which will in any case come back to us. It means we will be able to focus better on our work in hand by doing our best, without wasting our mental energy about what the results could be.
Since the results are sure to come back to us, it is always prudent to do our best, because we will get back the best fruits of it at some time, in some way, at some juncture (as schemed by God) for our betterment only!
Amma also used to point about two fruits in every action — one is drishta Phalam (visible result) and adrishta phalam (invisible fruit). Suppose a destitute boy who has not eaten for a couple of days knocks at our doors. Suppose we call the boy inside and offer him a sumptuous meal. As we watch the boy eating the food in a hurry and relishing every bit of it, it definitely gives us an instant joy. It is drishta Phalam. By feeding a poor boy, we acquire some punya to our credit. That is adrishta phalam.
If we had served the boy some stale food from the previous day’s remnants, he would have perhaps consumed it too to satiate his hunger. But by feeding him with fresh meals, we are offering our best. That satisfaction will be greater than offering him a stale food for sure. Giving the best definitely carries a bonus value!