When a repentant sinner turns to the Lord, the angels in heaven break out in joy.  When they see this evidence of the Father’s will being embraced on earth, as in heaven, it stirs them to song.  Every time a sinner has a change of mind, they cannot keep silent.  Heaven and earth are connected.  In Revelation 4 and 5 we get a glimpse of heavenly worship, in which the inhabitants of the earth are to join.  In Luke 15 the inhabitants of Heaven worship when they see God’s cause being advanced on the earth.  Let Heaven and earth rejoice together.

“I tell you, there is joy in the presence of the angels of God over one sinner who repents.” Luke 15:10 (NASB)