Sforno on Genesis 37:20/ספורנו על בראשית ל״ז:כ׳

1ועתה לכו, make up your minds quickly to kill him.

2אמרנו חיה רעה אכלתהו, so that Jacob will not have a chance of becoming angry at us and first be cursing us.

3ונראה מה יהיו חלומותיו, the dreams of which he told us that they foreshadow his rise to greatness and that he would rule over us. Then we will be witness to the fact that all these dreams will dissolve into nothingness and that they are nothing but lies.