It is narrated from Imam Musa Kazim/Kadhim (AS) who said: I found the knowledge that people need in four cases.
1.Know your God
2.Know what God has done for you
3.Know what God requires from you
4.Know what takes you out of your religion [1].
[1] Beharul Anwaar, Vol. 7, Page 32.
Source: en.shafaqna.com