ציטירנדיקער פּירוש אויף יחזקאל 20:30

The word לכן is a form of an oath as we know from Ezekiel 20,30-42. In that instance the prophet refers to our verse as something concerning which G'd had said: "I have raised My hand," i.e. a clear form of an oath.

והבאתי אתם AND I SHALL BRING THEM [INTO THE LAND OF THEIR ENEMIES] — I Myself shall bring them; this is a kindly measure for Israel in order that they should not say, “Since we are banished among the nations let us do like their doings”. “For”, says God “I will not suffer them to do this, but I will raise up My prophets and so bring them back under My wings, as it is said, (Ezekiel 20:30) “And that which cometh into your mind shall not be at all, — [that ye say, We will be as the heathens, as the families of the countries, to serve wood and stone]. As I live, saith the Lord God, surely with a mighty hand, and with an outstretched arm and with fury poured out, will “I” be king over you etc.” (Sifra, Bechukotai, Chapter 8 5).