What is the different between verb and verb to be?

A verb is a "doing" word and suggests an action, for instance "run... sing... dance..." are all dynamic verbs. The verb "to be" is an auxiliary verb and it can also be used as a main verb. It has eight different forms, for instance 'am' in 'I am late.' It is also known as a helping verb and expresses the main verb's mood, tense or voice.