Abide by and Hold fast

Abide by verb - Show respect towards.

Hold fast and abide by are semantically related In some cases you can use "Hold fast" instead a verb "Abide by".

Hold fast verb - Stick to firmly.

Abide by and hold fast are semantically related in conform topic. Sometimes you can use "Abide by" instead a verb phrase "Hold fast", if it concerns topics such as act in accordance with.