O blessed they

From Augustine, "Exposition on Psalm 148":

The subject of our meditation in this present life should be the praises of God; for the everlasting exaltation of our life hereafter will be the praise of God, and none can become fit for the life hereafter, who has not practiced himself for it now. So then now we praise God, but we pray to Him too. Our praise is marked by joy, our prayer by groans....On account of these two seasons, one, that which now is in the temptations and tribulations of this life, the other, that which is to be hereafter in everlasting rest and exultation; we have established also the celebration of two seasons, that before Easter and that after Easter. That which is before Easter signifies tribulation, in which we now are; that which we are now keeping after Easter, signifies the bliss in which we shall hereafter be. ....

Praise ye the Lord from heaven: praise Him in the high places. First he says, from heaven, then from earth; for it is God that is praised, who made heaven and earth. All in heaven is calm and peaceful; there is ever joy, no death, no sickness, no vexation; there the blessed ever praise God; but we are still below: yet, when we think how God is praised there, let us have our heart there, and let us not hear to no purpose, Lift up your hearts. Let us lift up our heart above, that it become not corrupted on earth: for we take pleasure in what the Angels do there. We do it now in hope: hereafter we shall in reality, when we have come there. Praise Him then in the high places. ....

What sort of command, think ye, have things in heaven and the holy angels received? What sort of command has God given them? What, but that they praise Him? Blessed are they whose business is to praise God! They plough not, they sow not, they grind not, they cook not; for these are works of necessity, and there is no necessity there. They steal not, they plunder not, they commit no adultery; for these are works of iniquity, and there is no iniquity there. They break not bread for the hungry, they clothe not the naked, they take not in the stranger, they visit not the sick, they set not at one the contentious, they bury not the dead; for these are works of mercy, and there is no misery, for mercy to be shown to. O blessed they! Think we that we too shall be like this? ....