Allah says here:
[أَوَلَمْ
يَكْفُرُواْ بِمَآ أُوتِىَ مُوسَى مِن قَبْلُ]
(Did they not disbelieve in that which was given to Musa of old) Did not
mankind disbelieve in those mighty signs which were given to Musa
[قَالُواْ سِحْرَانِ
تَظَـهَرَا]
(They say: "Two kinds of magic, each helping the other!'') cooperating or
working one with the other.
[وَقَالُواْ إِنَّا
بِكُلٍّ كَـفِرُونَ]
(And they say: "Verily, in both we are disbelievers.'') meaning, `we
disbelieve in each of them.' Because of the close relationship between Musa and
Harun, mention of one includes the other.