The lawsuit that is being filed is similar to one announced last week that alleges Indiana's laws banning same-sex marriage are unconstitutional.
Political analysts say the measure has less of a chance for approval in 2016 than it would have if it were on the ballot this year.
The House of Representatives voted to amend the proposed constitutional amendment banning gay marriage--a move that could restart the ratification process.
After hearing hours of testimony, the House committee chair delayed a vote on House Joint Resolution 3.
An Indiana-based conservative group is joining the public relations fight over the gay marriage amendment.
Legislators plan to debate a range of issues from a constitutional amendment banning gay marriage to a tax on office furniture.
Republican leaders say the decision to move forward on the amendment will be made internally by House and Senate Republican caucuses.
The ministers along with members of the Freedom Indiana coalition delivered the letter to the Statehouse Monday.
The Libertarian Party said today it would oppose a constitutional ban on gay marriage in Indiana, but a Tea Party group also said this week it would support it.
The Indianapolis-based media conglomerate echoed other groups in opposition to the bill, saying a constitutional ban on same-sex marriage could hurt business.