Don Johnson

Jesus not picking Matthias in the 40 days is an argument from silence.  There are lots of things Jesus did not talk about at all, or at least was not considered important enough to record.  Most scholars say that this is because much was assumed by a 1st century Jew and so does not need to be stated.  My poiny is when there is silence, fill in the gaps with the 1st century Jewish default understanding.  As a concrete example, Jesus is not recorded as speaking against fornication, houwever this was part of the general 1st century Jewish understanding of the OT.  So it is not too big a stretch to believe Jesus thought the same.

God knows everything that we will do, including what the 11 would do.  The 11 needed to start execising their authority, it is like learning to walk.  And Jesus had given them authority to execise, with the loosing and binding statements and others.