לֹא־יֹאבֶ֣ה יְהוָה֮ סְלֹ֣חַֽ לוֹ֒ כִּ֣י אָ֠ז יֶעְשַׁ֨ן אַף־יְהוָ֤ה וְקִנְאָתוֹ֙ בָּאִ֣ישׁ הַה֔וּא וְרָ֤בְצָה בּוֹ֙ כָּל־הָ֣אָלָ֔ה הַכְּתוּבָ֖ה בַּסֵּ֣פֶר הַזֶּ֑ה וּמָחָ֤ה יְהוָה֙ אֶת־שְׁמ֔וֹ מִתַּ֖חַת הַשָּׁמָֽיִם׃
Der Herr wird nicht bereit sein, ihm zu vergeben, aber dann wird der Zorn des Herrn und seine Eifersucht gegen diesen Mann entfacht, und der ganze Fluch, der in diesem Buch geschrieben steht, wird auf ihm liegen, und der Herr wird seinen Namen auslöschen unter dem Himmel;
Rashi on Deuteronomy
יעשן אף ה׳ THE ANGER OF THE LORD SHALL SMOKE [AGAINST THAT MAN] — Through anger the body becomes heated and smoke, as it were, issues from the nostrils. And thus does it state, (Psalms 18:9) “Smoke rose up in his nostril”. Although this idea is not really applicable to God, Scripture makes the human ear hear the matter (i.e. it tells it to him) in the manner that it is accustomed and able to understand according to the ordinary course of the world (i.e. when speaking of God it uses language that properly is applicable only to human beings because this the only language we have at our command).
Ramban on Deuteronomy
THE ANGER OF THE ETERNAL AND HIS JEALOUSY SHALL BE KINDLED AGAINST THAT MAN — this refers to the curse against the individual sinner, man or woman.
Sforno on Deuteronomy
לא יאבה ה' סלוח לו, when he will violate the covenant which he accepted as a sacred oath with his lips, although he had mentally had his reservations at the very time when he confirmed the covenant with his mouth.