Komentarz do Powtórzonego Prawa 4:3

YOUR EYES HAVE SEEN. Now Moses comes to forewarn on the details of the commandments, and he begins with [the prohibition against] idolatry which is the root of all [the commandments].

עיניכם הרואות, Moses reminds the people that they had observed the truth of this with their own eyes when their brethren, in their lust, not meaning to commit idolatry, had nevertheless done so, as they had been overcome by their libidos at the time so that they succumbed to seduction. The Torah testifies that their original sin had “only” been to whore with the daughters of Moav. (Numbers 25,1) The Torah, in outlawing sexual relations with non Jews had added that if this law was ignored the result would be intermarriage, idol worship by the children of such a marriage, etc. (Exodus 34,16) Every Israelite who indulged his lust for a Moabite girl had considered himself immune to such a warning. They proved to have been wrong, with the loss of 24.000 Israelites as a result. G’d had wiped out everyone of them who had worshipped Baal Peor. They had been tricked into it without realising it.

עיניכם הראות, "you have seen with your own eyes, etc." Moses meant that the Israelites had first- hand experience of the severity with which G'd punishes idol worship. G'd relates to that sin more harshly than to any other sin. He punishes even the people who have not actually served the idol with any of their limbs or their organs but have merely entertained idolatrous thoughts. G'd destroyed people who intended to worship Baal Pe-or. Kidushin 39 cites Ezekiel 14,5 as proof that G'd punishes the mere intention to indulge in idol worship.