stand fast vs stand firm

stand fast and stand firm both are verbs.

Word	Noun	Adjective	Verb	Adverb
stand fast	No	No	Yes	No
stand firm	No	No	Yes	No

As verbs, stand fast and stand firm are synonyms defined as:

Other synonyms of stand fast include hold firm, stand pat.

stand fast (verb)	stand firm (verb)
refuse to abandon one's opinion or belief	refuse to abandon one's opinion or belief
	stand up or offer resistance to somebody or something