Speaking to BBC2's Newsnight, Mr Blair, who switched from the Anglican church to Catholicism soon after leaving Downing Street, said: "You can be as religious as you like but the thing about praying to God is he doesn't tell you what the level of minimum wage is.
"I don't know what God's view of Brexit is and I don't think it's a sensible enquiry to have."
Mr Blair also rejected reports that he was plotting with French president Emmanuel Macron to force a new vote.
While the Labour member backs a second referendum that could see Britain stay in the EU, he denied telling European leaders to "hold firm" and pressure the Prime Minister into holding a new poll.
He asked: "How am I undermining it [Brexit]?
"I'm saying the country should come to a view in Parliament and if Parliament can't make up its mind or decides it wants to – you put it back to the people.
"What I'm saying to people privately in Europe is what I'm saying publicly."
He also called for a delay of nine to twelve months to give Parliament enough time to decide whether it wants a "soft Brexit, hard Brexit or no Brexit", with or without a second referendum.
Mr Blair described the Conservative Government as being "in a state of dysfunction".
He added: "Theresa May has taken this kind of extraordinary narrow view of this situation and just said 'Right, here is my deal. If you don't accept it then you're basically defying the will of the people, you're being unpatriotic'.
"Instead what she should be saying is 'OK, here is what Brexit really does mean. It can mean this if you go for a soft option, it could mean that if you go for a hard option. What do you want?'"
Meanwhile, a petition calling on Theresa May to cancel Brexit by revoking Article 50 has attracted more than 850,000 signatures.
The Parliament petitions website crashed on Thursday morning due to the high volume of traffic.
It comes as the prime minister heads to Brussels to ask the EU for a delay to next Friday's planned Brexit date.
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