Rabbi Roodyn

יב) שִׂמְחוּ צַדִּיקִים בַּה’ וְהוֹדוּ לְזֵכֶר קָדְשׁוֹ

Be glad in G-d you who are righteous and gratefully render homage to His holy memorial.

Rav Hirsch says that however distant this glorious future may still be, let the righteous of every generation rejoice in G-d, Who has revealed Himself particularly as the G-d of the future. And even if the ideal of the universal worship of Him will come to fruition only at some future time still veiled from our eyes, still He has bequeathed to us a זכר  a ‘memorial’ of this blissful state that will eventually prevail.

This ‘memorial’ is the treasure to be cherished in our hearts and spirits ‘for every generation’ one which should serve as our guiding light throughout all the dark days to come until the dawn of our promised brighter future. This is G-d’s precious gift which we acknowledge with grateful homage.