Hadiths 1.45 & 1.46

1.45:
Narrated Abu Huraira: Allah's Apostle said, "(A believer) who
accompanies the funeral procession of a Muslim out of sincere
faith and hoping to attain Allah's reward and remains with it
till the funeral prayer is offered and the burial ceremonies
are over, he will return with a reward of two Qirats. Each
Qirat is like the size of the (Mount) Uhud. He who offers the
funeral prayer only and returns before the burial, will return
with the reward of one Qirat only."

1.46:
Narrated `Abdullah: The Prophet said, "Abusing a Muslim is
Fusuq (an evil doing) and killing him is Kufr (disbelief)."
Narrated 'Ubada bin As−Samit: "Allah's Apostle went out to
inform the people about the (date of the) night of decree
(Al−Qadr) but there happened a quarrel between two Muslim men.
The Prophet said, "I came out to inform you about (the date
of) the night of Al−Qadr, but as so and so and so and so
quarreled, its knowledge was taken away (I forgot it) and
maybe it was better for you. Now look for it in the 7th, the
9th and the 5th (of the last 10 nights of the month of
Ramadan).