St. Gregory's Comment on this Sunday's Gospel

Statue of St. Gregory the Great in the facade of St. Stephen Basilica in Budapest, Hungary.

Here is this Sunday's Gospel reading:
Jesus summoned the Twelve and began to send them out two by two
and gave them authority over unclean spirits.
He instructed them to take nothing for the journey
but a walking stick—
no food, no sack, no money in their belts.
They were, however, to wear sandals
but not a second tunic.
He said to them,
“Wherever you enter a house, stay there until you leave.
Whatever place does not welcome you or listen to you,
leave there and shake the dust off your feet
in testimony against them.”
So they went off and preached repentance.
The Twelve drove out many demons,
and they anointed with oil many who were sick and cured them.
St. Gregory the Great has a brief comment on this passage:
"...the Lord sent the disciples to preach, two by two, because there are two precepts of charity, namely, the love of God, and of our neighbor; and charity cannot be between less than two; by this therefore He implies to us, that he who has has not charity towards his neighbor, ought in no way to take upon himself the office of preaching." (Hom. in Evan. 17)