{Neither let us commit fornication} (m(8864)e porneu(936d)en).
More exactly, And let us cease practicing fornication as some
were already doing ( 1Co 6:11  7:2 ). The connection between
idolatry and fornication was very close (see Jowett, _Epistles of
Paul_, II, p. 70) and see about Baal-Peor ( Nu 25:1-9 ). It was
terribly true of Corinth where prostitution was part of the
worship of Aphrodite. {In one day} (mi(8369) h(886d)er(8369)). An item that
adds to horror of the plague in  Nu 25:9  where the total number
is 24,000 instead of 23,000 as here for one day.