John Gill Commentary Mark 3:9

"And he spake to his disciples, that a little boat should wait on him because of the crowd, lest they should throng him:" — Mark 3:9 (ASV)

And he spoke to his disciples
In an authoritative way; he ordered and commanded them,

that a small ship should wait on him :
that a boat should be got ready, be near at hand, and attend him, who was on shore; that he might go into it, should there be any occasion for it; and from there preach to the people:

because of the multitude ;
which came from the above parts, and all together made a very numerous body of people:

lest they should throng him ;
crowd, press, afflict, and distress, and make him uneasy, that he could not be able to stand conveniently, and preach to them: so that should this be the case, as it was very likely it would, having a small vessel near the shore, he could go into it, and free himself from such an inconvenience.