Farron was asked by Channel 4 news as well as in parliament whether he thought homosexuality was a sin.
After initially giving the answer of "we're all sinners" to Channel 4's Cathy Newman, he later replied to the openly gay Tory MP Nigel Evans in the Commons stating "I do not."
The politician came under intense scrutiny with some the shadow chancellor John McDonnell stating on ITV's Good Morning Britain that it is "appalling" if Tim Farron believes homosexuality is a sin.
Responding to to the controversy on BBC's Newsnight, Mr Clegg said: "It's the privacy of his faith which he should be able to hold and hold dearly in the private way that many people hold faith to themselves.
"What he does as a legislator and as a politician that is a legitimate [concern].
"You should judge them not by their private faith but what their public actions are as legislators."