Why is the legacy mentioned first in the aayah, “after payment of legacies that you may have bequeathed or debts” [al-Nisa’ 4:12]?
Question

                Why is the word wasiyah (legacy, will, bequest) mentioned in the Qur’an before the word dayn (debt?) when we know that the debt must be paid off before the legacy is given?
Praise be to Allah.
    Al-Qurtubi (may Allaah 
    have mercy on him) said: “What is the reason why the legacy is mentioned 
    before the debt, when the debt takes precedence according to scholarly 
    consensus, i.e., the debts of the deceased must be paid off from his estate 
    before his will is executed… this may be answered in five ways: 

    1 – What is meant is that 
    these two issues take precedence over the issue of inheritance, and the 
    order in which they are mentioned is not indicative of which one is more 
    important. Hence the bequest was mentioned first. 

    2 – Because the legacy is 
    less binding than debt, it is mentioned first to show that it is 
    nevertheless important, as when Allaah says (interpretation of the 
    meaning): 

    “What 
    sort of Book is this that leaves neither a small thing nor a big thing…”

    [al-Kahf 18:49]

    … 

    4 – The legacy is mentioned first because it is the share of 
    the poor and needy, and the debt is mentioned second because it is the share 
    of the lender who can seek it with force and who has a strong argument to 
    support his case. 

    5 – Because the legacy is something that is initiated by the 
    person, it is mentioned first, whereas the debt is something that is well 
    established and clear whether he mentioned it or not. 

    See al-Jaami’ li Ahkaam al-Qur’aan by al-Qurtubi, vol. 
    5, p. 74. 

    Some scholars added two extra points: 

    “The legacy is mentioned first because the legacy is an act 
    of kindness and upholding family ties, unlike the debt which usually results 
    from a kind of neglect. So the phrase starts with the legacy because it is 
    of greater virtue.

    And it was said that the legacy is mentioned first because it 
    is something that is given for nothing in return, whereas the debt is given 
    in return for something. So payment of the legacy is harder for the heirs 
    than payment of the debt, and paying the legacy may be thought of as a form 
    of waste, unlike the debt which the heir will pay with condifence.” 

    See al-Tahqeeqaat al-Mardiyaah fi’l-Mabaahith al-Fardiyyah 
    by Shaykh Saalih al-Fawzaan, p. 27.