The compulsory duties in religion have been set forth in terms of the common man’s capabilities. But these duties indicate only the minimum of compulsory limits. Beyond these limits there are certain requirements, but these are of a voluntary nature, for example, the offering of the post-midnight prayer (tahajjud) in addition to the five compulsory prayers (fard salat) said at different times throughout the day, or charity in addition to the prescribed alms-giving (zakat), etc. This is the test of a man’s devoutness to see how many more good deeds he performs, thus making himself eligible for greater rewards.