religious belief vs religion

religious belief and religion both are nouns.

Word	Noun	Adjective	Verb	Adverb
religious belief	Yes	No	No	No
religion	Yes	No	No	No

As nouns, religious belief and religion are synonyms defined as:

religious belief and religion: a strong belief in a supernatural power or powers that control human destiny

Other synonyms of religious belief include faith.

religious belief (noun)	religion (noun)
a strong belief in a supernatural power or powers that control human destiny	a strong belief in a supernatural power or powers that control human destiny
	an institution to express belief in a divine power