Sunan an Nasai
1943
Sahih+2

It was narrated that Al-Mughirah bin Shu'bah said:"The Messenger of Allah said: "The rider should travel behind the Janazah and the pedestrian may travel wherever he wishes, and the (funeral) prayer should be offered for a child

SahihAbu Ghuddah
SahihAl-Albani