Musar su Salmi 35:10

Every Shabbos and Rosh Chodesh the ruach ascends to the upper Gan Eden where it receives the illumination and pure radiance of the neshamah. With this it descends to its place at the conclusion of the day. Afterwards the nefesh ascends and receives some of that illumination and radiance that the ruach brought with it from the neshamah in the upper Gan Eden. Then the nefesh descends and enters the grave where it takes the image of the body as it was when it was alive in this world and through this it clothes itself in a body, precisely as it was when the person was alive. In this manner the righteous stand upon their graves uttering words of praise and acknowledgement to God, may His name be blessed, for the lofty illumination of the neshamah, their faces radiating with great luminance. At that time they sing many songs and praises, precisely as they originally appeared, their bones knitted together and fleshed out like an actual body. If the living were allowed to perceive them they would see them at the conclusion of every Shabbos, Rosh Chodesh and Yom Tov in bodily form, standing upon their graves reciting songs and praises. This is the meaning of the verse, “All my bones will declare, Hashem, ‘Who is like You!” (Tehillim 35:10). Note that it is not stated that they “say” but that they “will say.” This is an allusion to the reciting of songs and praises by the dead at the conclusion of every Shabbos, Yom Tov and Rosh Chodesh.