Zechariah 7:5 - Speak unto all the people of the land, and to the priests, saying, When ye fasted and mourned in the fifth and seventh month, even those seventy years, did ye at all fast unto me, even to me?

Why do we do what we do? Do we serve God out of a heart of love or out of habit? In Heaven, our works will be rewarded according to the motives behind them. Those things we do for selfish reasons or for the praise of men will be burned by fire. Only those deeds we do for the glory of God will be rewarded.