Adam Clarke on Genesis 27:42

Doth comfort himself, purposing to kill thee - מתנחם לך mithnachem lecha, which Houbigant renders cogitat super te, he thinks or meditates to kill thee. This sense is natural enough here, but it does not appear to be the meaning of the original; nor does Houbigant himself give it this sense, in his Racines Hebraiques. There is no doubt that Esau, in his hatred to his brother, felt himself pleased with the thought that he should soon have the opportunity of avenging his wrongs.