1)
How will people know about the sticks, to ask about them?
1.
Radak: Hashem commanded him to write l'Eineihem 1 (in front of them).
2.
Malbim: They will see the miracle (they fuse), and ask about it, and about the Siman [of writing on the sticks].
1
It seems that he expounds "l'Eineihem" in verse 20. The simple meaning is, they will see the sticks in your hand. (PF)
