Hard work is its own reward

कर्मण्येवाधिकारस्ते
मा फलेषु कदाचन ।
मा कर्मफलहेतुर्भूः
मा ते सङ्गोस्त्वकर्मणि ॥

– भगवद्गीता

Your right is only to perform your duty. You do not have right to expect any consequences thereof. You should neither be motivated by the fruits of your action, nor should they encourage you to be inactive.

The reward of a thing well done, is to have done it.