"And Jesus went about all the cities and
villages, teaching in their synagogues, and
preaching the gospel of the kingdom, and
healing every sickness and every disease
among the people.
But when he saw the multitudes, he was
moved with compassion on them, because
they fainted, and were scattered abroad,
as sheep having no shepherd."
Matthew 9:35-36

The multitudes were becoming great.
Wanting to hear Jesus' preaching. He saw
these crowds as the whole world and the
harvest was plenty.

It was time to send out the twelve on
their own because the day was coming where
He would be leaving them and by them going
out it would multiply the work with more being
accomplished.