Numbers 17

"Now it came to pass on the next day that Moses went into the tabernacle of witness, and behold, the rod of Aaron, of the house of Levi, had sprouted and put forth buds, had produced blossoms and yielded ripe almonds." v.8

Read chapter 17
We see a rod blossom overnight.  It's not just a little sprout but blossomed and produced ripe almonds.  It's another sign (like Genesis 1) to show God can make something appear old even when it was just created (i.e. the earth and all that is in it).  And these are ripe or mature almonds, not just the flowers that become almonds.  Thus we see Jesus as a High Priest as a "rod [or root] out of Jesse" (Is. 11:1) and a "root out of dry ground" (Is. 53:2).
Of the twelve rods, representing the twelve tribes of Israel, Aaron from the house of Levi was chosen by God through whom He would forgive the people, that is the priesthood.    This budding of his rod overnight shows the speed and certainty of God's will.  All this was due from the Korah rebellion in the previous chapter when he and 250 other leaders wanted the same responsibility as Moses and Aaron.
When have you seen a clearly, obvious sign that the Lord has placed someone in a specific position?