Ibn 'Abbas said, " 'Umar said, 'Let us go forth to the land of
our people.' Ubayy ibn Ka'b and I were at the back of the people. A cloud
gathered. Ubayy said, 'O Allah, remove its harm from us!' We met the people
and their mounts were wet. They said, 'What fell on us did not fall on
you!' I said, 'He asked Allah Almighty to remove its harm from us.' 'Umar
said, 'Why didn't you include us in your supplication?'"