Then Jonathan said to him, Tomorrow is the new moon: and you will be missed, because your seat will be empty.
The shooting of arrows was probably just a practical way to signal David. Jonathan reminded David of their agreement as they parted (1 Samuel 20:23; cf. Genesis 31:48-53). [Note: For discussion of a minor textual problem in 1 Samuel 20:23, see Emunah Finkelstein, "An Ignored Haplography in Samuel," Journal of Semitic Studies 4:4 (October 1959):356-57.] 