कर्मण्यवाधिकार्स्तु मा फ़लेषु कदाचन

One should keep doing deeds without the expectations of fruits.

The above statement is true from some perspective. Lets see both the perspectives:

1. One will do deeds with the expectations of fruits: Definitely yes, one becomes a monk, in order to get moksha.

2. One will do deeds without the expectations of fruits: Sometimes this is true. when one does tapa, and out fluxes his karma- he still keep getting sufferings. For example: ParshwaNaath Bhagwaan did some much tapasya in his last births, but got some many sufferings from Kamath. In such case, someone may lose his patience and leave the right path to Moksha. In such case, one should not expect his deeds to necessarily show up good fruits in short term. He may have many sifferings in between because of his previous bad karma, which he does not know- how many they are in store.

So the conclusion is, on the path to Moksha, if one is not getting success in getting peace-he should keep patience- should not stumble in between if sufferings because of past karmas come in the way.