{Unto his disciples} (pros tous math(8874)as autou). So Jesus
turns from the crowd to the disciples (verses  22-40 , when Peter
interrupts the discourse). From here to the end of the chapter
Luke gives material that appears in Matthew, but not in one
connection as here. In Matthew part of it is in the charge to the
Twelve on their tour in Galilee, part in the eschatological
discourse on the Mount of Olives. None of it is in Mark. Hence Q
or the Logia seems to be the source of it. The question recurs
again whether Jesus repeated on other occasions what is given
here or whether Luke has here put together separate discourses as
Matthew is held by many to have done in the Sermon on the Mount.
We have no way of deciding these points. We can only say again
that Jesus would naturally repeat his favourite sayings like
other popular preachers and teachers. So  Lu 12:22-31 
corresponds to  Mt 6:25-33 , which see for detailed discussion.
The parable of the rich fool was spoken to the crowd, but this
exhortation to freedom from care ( 22-31 ) is to the disciples.
So the language in  Lu 12:22  is precisely that in  Mt 6:25 . See
there for m(8820)merimn(8374)e (stop being anxious) and the
deliberative subjunctive retained in the indirect question
(phag(8874)e, endus(8873)the). So verse  23  here is the same in  Mt
6:25  except that there it is a question with ouch expecting
the affirmative answer, whereas here it is given as a reason
(gar, for) for the preceding command.