During your life, you will attend a divine school. It is the school of obeying God. This obedience is achieved by intending to draw close to God through performing the religious duties that He imposed on you.
These duties are related to:
1. Mind, such as: meditation, calling the soul to account, etc
2. Speech, such as: glorifying God by the tongue, reciting Qur'an, etc
3. Money, such as: giving alms, paying the fifth of the money, offering the desirable charity, etc
4. Groups of People, such as: group praying, etc
5. Practice, such as: pilgrimage rituals, performing prayers, etc
6. Appearance, such as: veiling, grooming, adorning, etc
7. Relationships, such as: obeying parents, keeping connection with kins, ordering with what is good, forbidding what is bad, intermingling between males and females, etc
“And I created not the jinns and humans except they should worship Me” [Surah Ad-Dhariyat, 51:56]
You must know the specific conditions and details related to these duties. You have to know them in order to clear yourself before The Most High God. The science that clarifies these details and conditions for you is called "jurisprudence".
The science that guides you to acquire good morals is ethics. It helps you to perform them in order to get close to God and to please Him and not people. Also, it puts for you the program for performing these duties, preaches you of the hereafter, and guides you to avoid the corrupted morals, such as: arrogance, love of this world, etc.
If God loves a certain human being, He makes him/her a jurisprudent in religion.
Imam Al-Sadiq (God's peace bestowed upon him)