Tahajjud salaah

There is great virtue in getting up in the middle of the night and offering salaat. This is called tahajjud salaat. This salaat is most acceptable in the sight of Allah, and one gets the most reward for it. The minimum for tahajjud salaat is four rakaats and the maximum is twelve rakaats. If not, even two rakaats will suffice. If one does not have the courage to offer it later, then he could offer it after Esha. However, he will not receive the same reward.

And Allah Ta'ala (الله تعالى) knows best.