Q. Since we have a duty to keep the mitzvot, how can we say we enjoy it?
A. Why do we observe the commandments? In theory it is because they are given by God, but many people prefer to say that the mitzvot show our Jewish identity, make our lives rich and poetic, and symbolise great principles.
For true believers who follow the first approach, there really is a problem. If we observe in order to obey, who do we need to talk about enjoying it? And if we say we observe out of enjoyment, why do we need a command?
There actually were ascetics who tried to observe without a smile and almost preferred to feel miserable and not derive any joy out of their obedience. Most of us would say this is both bizarre and impossible, and would find support in the Tochachah, the Biblical curses, which say that God punishes those who do not serve Him with joy (Deut. 28:47).
In that sense, rejoicing is also a Divine commandment, though the command is not “You shall rejoice” but “You shall serve God with joy”.