Q: Is there hadith encouraging or discouraging first maternal and or paternal cousins to marry each other?

A: We haven't come across any Hadith discouraging the marriage with first cousins. In fact Rasulullah (Sallallahu Alayhi Wasallam) married his first cousin, Hazrat Zainab bint Jahsh (Radiyallahu Anha).

And Allah Knows Best
Darul Ihsan Fatwa Dept.