The Ruling on Giving a Layman Fatwā Outside the Madhhab

Answer (and Allah grants success):
Islam is built upon ease, facilitation, and relief—just as Allah the Exalted
has said:
“…and He has not placed upon you in the religion any hardship—the
way of your father Abraham. He named you Muslims…” — [al-Ḥajj 22:78]
“Allah intends for you ease and does not intend for you hardship.” — [al
Baqarah 2:185]
“Allah wants to lighten [the burden] for you; and man was created
weak.” — [al-Nisāʾ 4:28]
And in the narration: “Make things easy and do not make them
difficult.”
On this basis, there is no harm in giving the layman fatwā outside the
madhhab, or outside the madhhab of the muftī, from among the
madhhabs of the Imams of the Ahl al-Bayt (ʿa), so long as it entails ease
and facilitation. The condition is that the madhhab of that Imam is
authentic.
We have restricted ourselves with our saying “correctly” from of some
madhhabs that are attributed to the Imams through takhrīj (derivation)
and branching upon their madhhabs, but these do not actually constitute
their madhhabs. Derivation may or may not be valid, and an Imam may
or may not have intended it. If we give a layman fatwā on such a basis, it
may be that we have given him what is not permissible.
Objection: The layman’s question to the muftī is itself a commitment
to the madhhab of the muftī, as indicated by Allah’s saying:
“So ask the people of the message if you do not know.” — [al-Anbiyāʾ 21:7]
Response: The verse indicates that it is obligatory on the layman to
act upon what the muftī has given him fatwā with, but it does not
indicate that the muftī must issue fatwā only according to his own
madhhab, or any specific madhhab.
Objection: The layman chose this muftī among the scholars in order
to receive fatwā in his madhhab, not another.
Response: The layman chooses the muftī out of trust and good
opinion of him—because he sees him as more knowledgeable, or more
ascetic and pious, or due to his worship and chastity—and because he is
confident that he will give him only a correct madhhab by which he is excused before Allah Most High.
Indeed, within the madhhabs of the Imams of the Ahl al-Bayt (ʿa) is
what suffices for their followers to be excused before Allah, as the
Prophet (May Allah bless him and his family and grant them peace) said:
“My Ahl al-Bayt are like the stars—whenever one sets, another rises.” And
he (May Allah bless him and his family and grant them peace) said: “Learn
from them, and do not teach them.” And he said: “My Ahl al-Bayt are like
the Ark of Noah: whoever boards it is saved, and whoever lags behind it is
drowned and ruined.” And he (May Allah bless him and his family and
grant them peace) said: “I leave among you that which, if you hold fast to
it, you will never go astray after me: the Section of Allah and my progeny,
my Ahl al-Bayt. The Subtle, the Aware has informed me that they will never
separate until they return to me at the Ḥawḍ.” And other ḥadīths, too numerous to be counted.