Ezekiel portrays the LORD himself seeking, rescuing, gathering, feeding, and binding up his scattered sheep. Jesus' searching shepherd stands naturally within that divine-shepherd promise, though Luke does not quote Ezekiel here.

Israel's Scriptures repeatedly picture God as shepherd and God's people as sheep needing gathering and rescue. Psalm 119:176 is especially close to the confession of being a lost sheep, but it is not identified by Luke as the parable's source.

The extravagant search, compassion, restoration, and joy are consonant with Scripture's repeated portrayal of God as merciful and compassionate. This is a theological thread rather than a direct quotation.

Luke repeatedly makes Jesus' table fellowship with tax collectors and sinners a flashpoint. Luke 15 explains the divine logic behind that welcome: recovery of the lost is cause for joy.

Jesus has lamented his desire to gather Jerusalem and then described a banquet whose seats are filled unexpectedly. Luke 15 now makes finding, restoring, and feasting the emotional center of God's welcome.

Each lost/found movement climaxes in rejoicing. The father's repeated 'dead/alive, lost/found' explanation interprets the feast as the narrative equivalent of heaven's joy over repentance/restoration.

Grumbling over Jesus receiving a sinner, joyful welcome, repentance, restoration, and lost/found language make Zacchaeus a narrative enactment of Luke 15. Jesus then summarizes the same mission logic: the Son of Man came to seek and to save that which was lost.

The lost coin deliberately repeats the lost-sheep pattern: something valued is lost, the owner searches until it is found, others are summoned to rejoice, and Jesus interprets the joy in terms of a sinner who repents.