Jabir said, " "Someone riding should greet someone walking, and
someone walking should greet someone sitting down. When there are two people
walking, the better of them is the one who gives the greeting first."
Ibn 'Umar said that al-Agharr (who was a man from Muzayna and had
been a Companion of the Prophet) was owed some measures of dates by a man
from the Banu 'Amr ibn 'Awf who came to him many times. He said, "I went
to the Prophet, may Allah bless him and grant him peace, and he sent Abu
Bakr as-Siddiq with me." He continues, "Everyone we met greeted us. Abu
Bakr said, 'Don't you know that when people give the greeting before us,
they have the reward? Give the greeting before them and you will have the
reward.'"
'Abdullah ibn 'Amr reported that the Messenger of Allah, may Allah
bless him and grant him peace, said, "Worship the All-Merciful and feed
people. Make the greeting common practice among you and you will enter
the Garden."