The Shari`a ("way") is the sum total of God's unchanging will for
human behavior. The term is therefore used to designate Islamic law as a whole,
or as an abstraction.
Fiqh ("understanding") is the human endeavor to determine what God's
will is in any concrete situation. The term is therefore applied to the science
of law, and to the body of detailed regulations that make up actual statements
of Islamic law (its "branches" as opposed to its "roots").
Here is an outline of the topics discussed in one very typical short manual
of fiqh (by the Malikite scholar Ibn Abi Zayd):
Belief, which receives only brief treatment, but is necessary for
obedience to be valid.