Quora answer:

hypocrites. for belief can not be just lip service. The God, & there is no god but He, Who has no partners, Created us for worship. Everyone/thing He has Created, worships Him in one way or another & are obedient to Him. Only man & jinn have a will to choose to believe or not, & if they say they believe, have also, the will to worship, back up that claim of belief with actions, as The God says that most of His Servants (among man & jinn) do not “act” with gratitude. So gratitude is not only to say “I thank You” but believers back up that with actions of gratitude.