Luke 9:5
And whosoever will not receive you, when ye go out of that city, shake off the very dust from your feet for a testimony against them.
Cross-reference
Luke 9:48 ties welcoming a child to welcoming Jesus, contrasting the rejection in 9:5 with the blessing of acceptance.
Luke 10:10-11 parallels the dust-shaking command for the 72, adding a verbal warning about the kingdom's nearness.
Luke 10:16 links rejection of disciples to rejection of Christ and the Father — the theological basis for the dust-shaking testimony.
Matthew 10:14 is the parallel account of the same instruction to shake dust off feet when not welcomed.
Matthew 10:15 gives the judgment consequence — it will be more bearable for Sodom than for that town.
Mark 6:11 is the parallel version of the same commissioning instruction to shake dust as a testimony.
Acts 13:51 records Paul and Barnabas actually shaking dust off their feet, enacting the instruction from Luke 9:5.
Acts 18:6 has Paul shaking out his clothes as a similar symbolic testimony of rejection, echoing the dust-shaking gesture.
Nehemiah 5:13 uses shaking out a robe as a symbolic curse — a similar OT action of judgment and rejection.
Mark 9:37 speaks of welcoming a child in Christ's name — the positive counterpart to the rejection in Luke 9:5.