And Israel dwells in safety,
The fountain of Jacob alone,
In a land of grain and new wine;
Yes, his heavens drop down dew.
Because of this Israel, once they had driven out their enemies and are alone in the land, will dwell in safety and prosperity, having reached the land of grain and new wine, whose heavens drop down dew (which helps to produce the grain and new wine). Note the assumption of aloneness. Moses indicates his expectation that they will be obedient and thus will have turned out the Canaanites (possibly with his tongue in his cheek).
“The fountain of Jacob.” That which springs forth from Jacob.