It often happens, in the Psalms, that you can scarcely tell whether it
is David, or the Lord Jesus, or both of them, to whom the writer is
referring. Oftentimes you lose sight of David altogether, and are quiet
certain that he is not there; while, at other times, the words seem equally
suited either to David as the type, or to Jesus as the antitype. I think
that this fact is very instructive to us. It is as the Holy Ghost intended,
even in those ancient times, to let God's saints know that there is a
mysterious union between Christ and His people, so that almost all things
which may be said concerning Him may be said, also, concerning those who are
in Him. They are so completely one, they are so intimately united in bonds
of mystic, vital, conjugal, eternal union, that it would not be possible
always to keep the sayings concerning them apart. -- Charles Spurgeon