100. " o' you who have faith! if you hearken to a party from among of those
who have been given the book, they will turn you back, after your faith,
into disbelievers."

commentary:
in several commentary books it is cited that one of the jews by the
name of shash-ibn-qays once passed by the gathering of muslims
consisting of members of two tribes called 'aus and khazraj and saw that
they were very sincere with each other. he became worried about it and
said to himself that formerly these two tribes were opposite to each other,
but now, under the leadership and direction of muhammad (p.b.u.h.), they
are living with each other peacefully. if this leadership continues, the
existence of the jews will be in danger.

he, systematically gathered a group to help him, and commissioned a
young man to go inside them and to excite them by reminding them the
memories of their fight in biq­ath
(the place where those two tribes fought
against each other),
so that the fire of a hard combat was going to be lit
between them. the prophet of islam (p.b.u.h.), with his soothing words,
warned them and made them aware of that evil plot. therefore, they put
their swords down and kindly embraced each other while they were
shedding tear and were regretful.

according to the commentators, in this incident, the above verse and
the two former verses were revealed which caused the reproach and blame
of the people of the book as well as warning the muslims.

" o' you who have faith! if you hearken to a party from among of those who
have been given the book, they will turn you back, after your faith,
into disbelievers."