“I tell you that in the same way, there will be more joy in heaven over one sinner who repents than over ninety-nine righteous persons who need no repentance” (Luke 15:7).
Federal Visionists love this verse because they think that Jesus is talking about the joy in heaven over each conversion. Notice how Federal Visionists equate repentance with conversion. They even argue that repentance can be a synonym for conversion. However, this is inconsistent with Reformed categories of Systematic Theology.
The Reformed faith has always insisted that justification is by faith alone. This means that repentance is not part of justification. Repentance is a work, and thus, repentance is part of sanctification.
While heaven might rejoice over conversions, we cannot say this with confidence because Jesus is not speaking about conversions. He is speaking about repentance, or sanctification. Thus, heaven rejoices over sanctification.