Rashi on Numbers 31:16/רש"י על במדבר ל״א:ט״ז

1הן הנה BEHOLD, THESE [WERE AN ENTICEMENT TO THE CHILDREN OF ISRAEL] — These: this word tells us that they recognised them, saying, ‘This is the woman through whom so-and-so fell into sin” (Yalkut Shimoni on Torah 785).

2בדבר בלעם [THESE WERE AN ENTICEMENT] THROUGH THE WORD OF BALAAM — He had said to them: Even if you bring together all the hosts that are in the world you cannot overcome them. Are you perhaps more numerous than the Egyptians who had six hundred chosen chariots? Come and I will give you counsel: Their God has a hatred of immorality, etc., as it is related in the chapter חלק (Sanhedrin 106a) and in Sifrei Bamidbar 157:6.