عَبَدَ is more than the bare idea ‘to worship.’
It is a conjugated past form meaning ‘he worshipped.’ The action is worshipping, while the hidden pronoun هُوَ identifies the doer.
So we analyze it as:
عَبَدَ = worshipped + hidden هُوَ
The pronoun is understood from the form even though it is not written separately.