come to jesus
Originally an emotional experience that is life changing, it has evolved to mean a serious argument, one that better result in a change of action or else.
Example; My husband and I are going to have a "come to jesus" over this remodeling job. or I'm going to have a "come to jesus" with that kid about his drinking and partying.
*This phrase was very unpopular over at "Urban dictionary" What can I say - Jesus usually is.