In the Name of Allaah, the Possessor of Infinite Mercy, the Justly Merciful…
Allaah says: 
From the Sunnah of the Prophet (sallallaahu ‘alayhe wa sallam):
“Verily Allaah has given every person his true rights, so there can be no wasiyyah (bequethal) for a waarith (one who receives irth), and the child is for the (owner of the) bed, and the fornicator gets the stone (ie. nothing)…” 
Here the Messenger (sallallaahu ‘alayhe wa sallam) forbids the one who receives irth from also receiving a wasiyyah. So obviously they are two separate things with different rulings.
What exactly is a wasiyyah then?
Ibn Rushd Al-Hafeed (d.595), the author of Bidaayatul-Mujtahid, said, “The wasiyyah in a nutshell is a man giving a gift from his wealth to another or a group of people after his death, or that he frees his slave, whether he mentions the word ‘wasiyyah’ specifically or not.” 
So the wasiyyah is that which is given to someone according to the wishes of the deceased. It can be expressed verbally or in writing, and then it is witnessed. In the West, it is similar to when a man writes someone in his will to receive his house, car, or a sum of money.
We have been prohibited from taking the irth (inheritance) of the non-Muslims, according to the authentic hadeeth:
The statements of the scholars concerning a Muslim’s wasiyyah to a non-Muslim
With regards to a Muslim giving a wasiyyah to a non-Muslim, the scholars have unanimously agreed that it is permissible.
Ibn ‘Abdil-Barr (d.464) said, “There is no differing among the scholars that I know of over the permissibility of a Muslim giving a wasiyyah to his non-Muslim relative, since they do not inherit from him. And Safiyyah bint Huyay gave a wasiyyah to her Jewish brother.” 
Ibn Qudaamah Al-Maqdisee (d.620) said, “The permissibility of a Muslim giving a wasiyyah to a thimmee (non-Muslim living under Muslim rule) has been reported from Shurayh, Ash-Sha’bee, Ath-Thawree, Ash-Shaafi’ee, Is-haaq, and the Hanafees. I do not know anyone who differed with them.” 
Al-Maardeenee (d.912) said, “It (the wasiyyah) is allowed to be given to the poor people of a specific area, or a band of them, and to a thimmee, a young child, or an insane person by agreement of the scholars.” 
The statements of the scholars concerning the kaafir’s wasiyyah to a Muslim
The scholars have also agreed that a Muslim may accept the wasiyyah of a non-Muslim.
Ibn Al-Munthir (d.318) said, relating a consensus, “All of the people of knowledge that we take from have agreed that the wasiyyah of a thimmee (a non-Muslim living under Muslim rule) is permissible, so long as the thing given itself is permissible to possess.” 
Ibn Rushd Al-Hafeed (d.595), said, “And the wasiyyah of a non-Muslim is permissible to take according to them (the imaams), so long as the wasiyyah is not something haraam in itself.” 
Ibn Qudaamah Al-Maqdasee (d.620) said, “So when it is permissible for a Muslim to give a wasiyyah to a thimmee, then a thimmee’s wasiyyah to a Muslim, or to another thimmee, has even more right (to legitimacy).” 
Muhammad ibn Saalih Al-‘Uthaymeen (d.1421) said, “If someone asks, ‘How can one’s parents not be considered waariths (inheritors)?’ The answer: That is possible, like when the mother or father has a different religion, then they do not take any irth, rather they can be given a wasiyyah(instead).” 
Fulaan (like saying So-and-So in Arabic) is a Muslim. If one of Fulaan’s non-Muslim relatives dies, leaving for Fulaan a sum of money or some kind of property or wealth, having specified it for Fulaan, either in writing or by speech or gesture, and, as a result, that wealth is then offered to Fulaan, then it is permissible for Fulaan to accept it, and it is from Allaah’s halaal provisions for him. And Allaah is al-Muwaffiq, the One who grants success.
Written by: Moosaa Richardson
ST Archives: 04-11-2003
 The meaning of Soorah An-Nisaa’ 4:11
 Saheeh Sunan At-Tirmithee (#2120)
 Bidaayatul-Mujtahid (4/180)
 Al-Bukhaaree and Muslim
 At-Tamheed (13/239)
 Al-Mughnee (8/512)
 Irshaad Al-Faaridh (p.275)
 Al-Ijmaa’ (p.275)
 Bidaayatul-Mujtahid (4/173)
 Al-Mughnee (8/512)
 Tafseer Soorah Al-Baqarah (2/309)