1 Samuel 11:8

And there were three hundred thousand sons of Israel, etc. There were in the people of the nations, those who were most ready to defend the faith, who believed rightly, hoped, and acted through love. For the number three, because of the confession of the Holy Trinity, is to faith; ten and a hundred because of the choice of the reward of the right hand, and the daily denarius to be given to good vineyard workers, are related to hope. Moreover, a thousand because of the solid nature of the denarius, which naturally looks to the immutable and stable operation of perfect love, it can rightly be understood in the same Church either of the Jews or of the nations, by the strength of the men of Judah first confessing God; but by the sons of Israel, the sublimity of those who have learned to contemplate Him more perfectly, as the Psalm says: "God is known in Judah, His name is great in Israel." It is to be noted that according to the letter much before the times of Rehoboam, the son of Solomon, separately the tribe of Judah, but separately also the others that were called Israel, were counted, although not yet divided by empire or religion.

9. First the children of Israel are said to have gone out, then to have been mustered by Saul, because the chosen preacher, when he attempts to move the soldiery of his subjects against hidden enemies, first observes their brave resolve, then places them in the number of warriors. For we are, as it were, inside and cannot be mustered, as long as the virtue of our mind is hidden from our pastors. And when we go out we are mustered, because when we reveal to them the fortitude of our minds, they trust that they now have companions in the spiritual fight. But when they desire to raise weak minds to the resolve of good work, they strive not only to instruct us with the teachings of the greater ones, but also to kindle us with the examples of the lesser elect. Rightly therefore it is reported that three hundred thousand of the children of Israel, but thirty thousand of the men of Judah, were mustered. For the number thirty pertains to the rectitude of faith and the zeal of good works, because the precepts of the law are nothing if they do not tend toward the contemplation of the supreme Trinity. Fittingly therefore they are called men of Judah who are contained in thirty thousand, because they have the confession of right faith and the strength of good works. Our fathers, however, were of the same faith and works, but in the contemplation of divinity, inasmuch as they had advanced far higher than we, they also displayed stronger works of faith. Wherefore also three hundred thousand of the children of Israel are mustered. Thirty indeed comes from three and ten, and ten goes into thirty, but in the number thirty both the ten and the three are simple; but in order to count up to three hundred, we multiply ten by thirty and thirty by ten, because even if the contemplation is great and the works of the subject people are great, nevertheless those which preceded in our fathers were incomparable. For it is as if our number ten is gathered tenfold in their perfection, since our achievements are greatly subordinated to their perfection. Therefore thirty thousand men of Judah and three hundred thousand children of Israel, mustered with us, lead preachers to fight against Nahash — if, when they wish to help tempted and abstinent subjects, they set before them both the outstanding deeds of the strongest fathers and those of the lesser ones. Israel indeed is interpreted as…