“Gather together, come, draw near, all you … who … pray to a god that cannot save you”. 

Isa 45:20 NEB 

Many people find as they go through life that they have previously made a bad decision that stays with them for a long time. Some choose the wrong career, marry the wrong partner, buy the wrong house, join the wrong church, and so on. Some can later be put right. Others can’t. And some, thinking that religion is not for them, choose other gods that, whether they realize it or not, are going to leave them strangely unfulfilled and empty. 
The people of Babylon were like that and Isaiah didn’t hesitate to tell them how wrong they were. Some of the Israelites had also done so. Long before they were carted off to Babylon plenty of them were secretly going off to the temples of the Canaanites in Israel who worshipped gods and goddesses of fertility. The worship included visiting sacred prostitutes, and thus those Israelites who made a practice of this were committing adultery. This left them with guilt and a sense of alienation from their own God. 
Plenty of people today follow false gods that cannot save them. The main one is money. Some people make the pursuit of wealth the be-all and end-all of life. Whilst affording some degree of comfort it usually also leaves people feeling lost and disorientated. It is a god that cannot save. Another is nationalism. People elevate their nation to the status of a god and see life and the world from the narrow and exclusive vantage point of an ideology. 
Work out what your own false god is and ask whether it can truly save you – however fervently you pray to it. 

Lord, preserve me from worshipping bad gods.