Or HaChaim on Deuteronomy 1:10/אור החיים על דברים א׳:י׳

1 ה׳ אלוקיכם הרבה אתכם, "The Lord your G'd has multiplied you, etc." This sounds peculiar as we have not read anywhere that the Jewish people had multiplied and become more numerous than the number of people who had participated in the Exodus. Neither did the Israelites increase since the census in the second year of their wanderings. Our sages in the Sifri understood the reference as meaning: "He has made you greater than your judges." Perhaps another thing which Moses had in mind with these words is something we have been taught in the Zohar volume 3 page 211 that when one mentions the abundance of good, its power is increased when it comes to warding off evil influences. The Zohar writes there that whenever one mentions G'd's name as the supreme G'd, the spiritually negative influences lose their power to exercise dominion. Seeing that Moses had first complained that he himself could not handle the Jewish people by himself, he felt it necessary to invoke this Name to counteract any negative influences he might have awakened by his comment.

2והנכם היום, "and here you are as of this day, etc." Moses was very careful to say היום, "today," to alert us to the fact that the statement is to be divided into two separate time frames. The first time frame related to the period during the second year of their wanderings when he had told G'd that he was unable to bear the burden of leadership all by himself. Concerning that period, he had said "G'd has mutiplied you, etc." The second time frame concerned the present, i.e. the fortieth year of their wanderings as he pointed out "as of today you are as numerous as the stars in the sky."

3ככוכבי השמים, "as the stars in the sky." When Moses said these words he referred to something we have learned in Sanhedrin 26 that אין מנין לרשעים, "that the wicked do not really have a number." What the Talmud means is that though from a numerical point of view the wicked may appear to number a great many, their increase in number does not imply an increase in importance. The very reverse is true of the righteous. Though, numerically speaking, they may appear as insignificant, their influence is totally disproportionate to their actual number. This is precisely what Moses had in mind when he compared the "number" of the Israelites to the stars in the sky. Just as each of the stars is an important unit in its own right, so each one of the Israelites contributed to the importance represented by their collective רבוי, multiplicity.