7 “Let all the kings of the earth confess to You, O Lord”. So shall it be, and so it is, and that daily; and it is shown that it was not said in vain, save that it was future. But neither let them, when they confess to You, when they praise You, desire earthly things of You. For what shall the kings of the earth desire? Have they not already sovereignty? Whatever more a man desire on earth, sovereignty is the highest point of his desire. What more can he desire? It must needs be some loftier eminence.
But perhaps the loftier it is, the more dangerous. And therefore the more exalted kings are in earthly eminence, the more ought they to humble themselves before God. What do they do? “Because they have heard all the words of Your mouth.” In a certain nation were hidden the Law and the Prophets, “all the words of Your mouth:” in the Jewish nation alone were “all the words of Your mouth,” the nation which the Apostle praises, saying, “What advantage has the Jew? Much every way; chiefly because that unto them were committed the oracles of God.”
These were the words of God....What meant Gideon's fleece? It is like the nation of the Jews in the midst of the world, which had the grace of sacraments, not indeed openly manifested, but hidden in a cloud, or in a veil, like the dew in the fleece. The time came when the dew was to be manifested in the floor; it was manifested, no longer hidden. Christ alone is the sweetness of dew: Him alone you recognise not in Scripture, for whom Scripture was written. But yet, “they have heard all the words of your mouth.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)