Rashi on Numbers 14:28/רש"י על במדבר י״ד:כ״ח

1חי אני AS TRULY AS I LIVE — This is a formula of taking an oath: If I do not do so, then — if this were at all possible to say of God — I do not live.

2כאשר דברתם AS YE HAVE SPOKEN … [YOUR CARCASSES WILL FALL IN THE WILDERNESS] — because you made the request of Me: “Would that we had died in this wilderness” (Numbers 14:2).