Members of President Carter's church here decisvely defeated an attempt last night to reconsider an earlier decison of the congregation to dismiss their pastor, the Rev. Charles Trentham.

In a 3 1/2-hour session, the regular quarterly meeting of the First Baptist Church voted Thentham a severance pay package of $33,012, which they termed payment for a "predretirement sabbatical."

On Oct. 28, a specially convened meeting of the congergation voted to dismiss Trentham, effective Feb. 1, for dating a 28-year-old woman who had separated from her husband but whose divorce was not final. The woman is the daughter of a church member who frequently shares Sunday school teaching duties with the president.

The special severance package was proposed as a compromise that all parties in the bitterly divided congregation could accept. Under the provisions of the church's personnel policy, Trentham, who has been at the church for six years, would normally have received about $7,000 in severance.

A straw poll last night on the amount congregation members would be willing to contribute toward the $33,012 severance payment beyond their regular donations to the church totaled about $21,000. It was unclear last night how the church members settled on the final severance figure.