﴿ فَتَنَٰزَعُوٓا۟ أَمْرَهُم بَيْنَهُمْ وَأَسَرُّوا۟ ٱلنَّجْوَىٰ ﴾

“So they debated among themselves as to what to do; but they kept their counsel secret,”

(Then they debated one with another what they must do) they consulted with one another and decided that if Moses defeats them, they will believe in him, (and they kept their counsel secret) from Pharaoh.