Tobit 13:17

But that you may rejoice in the promise of following joy, learn the songs of eternal praise written in this volume: "Blessed are they who dwell in your house, O Lord, they shall praise you forever and ever." And as it is said by a certain wise man concerning the heavenly Jerusalem: "And all its streets shall be paved with precious and pure stone, and through all its lanes alleluia shall be sung." The citizens of the heavenly homeland had come to announce this song to us, who cried out in harmony: "Glory to God in the highest, and on earth peace to men of good will."

Thus our custom is to chant "Alleluia" more frequently and happily during these fifty days in memory of this, our most peaceful and blissful action. Alleluia is a Hebrew word, and in Latin it means "praise the Lord!" Accordingly, where we chant in the psalms, "Praise the Lord," in place of this expression among the Jews "Alleluia" is always chanted. In his book of Revelation, John the Evangelist mentions that he had heard the throngs of heavenly virtues singing it. And when the venerable father Tobit had understood from an angelic vision what the glory of the citizens on high is, and the great brightness of the heavenly Jerusalem, he said the following with mystical voice, "All its streets are paved with precious and shining stones, and throughout all its districts 'Alleluia' will be sung."It is most proper and beautiful that a general custom has prevailed in holy church of all the faithful throughout the world singing this word of praise in the Hebrew language, out of reverence for the primitive practice. This has come about so that, through the harmony of such a devotion, the whole church may be admonished that now it ought to consist in one faith, confession and love of Christ, and in the future it ought to hurry to that land in which there is no discord of minds, no disharmony of speech. For just as once in Jerusalem the heart and soul of the multitude of the believers was one and all things were theirs in common, so in the "vision of supreme peace" the heart and soul of the entire multitude of those who see God will be one, loving and praising him by whose grace they see that they have been saved. There everything will truly be theirs in common, for, as the apostle says, "God will be all in all."

Then the elder Tobias, opening his mouth, blessed God. Confessing His severity and mercy, and at the same time admonishing His faithful to always proclaim His benefits, to fear His scourges; imbued with the spirit of prophecy, he chants many praises concerning our heavenly mother, Jerusalem. And the people of the Jews, converted at the end of the world to faith, will have many teachers and prophetic men who will inflame the minds of their neighbors with heavenly desires, while they frequently resound with the perpetual joys of the heavenly fatherland.

Will I ever be able to see what is so desirable, what the angels long to gaze on, so I can say, "Look, now I see what I have so longed for, what I wanted I now possess!"? When will I come and appear before the face of the Lord, to contemplate him in the blessedness of his elect, to know the joy of his people and to glory in his inheritance? When will I see that city of which it is said, "Your squares, Jerusalem, will be paved with pure gold, and in you will resound a hymn of exultation, and in all your streets they will say, 'Alleluia!' "? O holy city, O splendid city! I salute you from afar, I invoke you, I seek you. I desire to see you and to rest in you, but the flesh that holds me back does not let me do so. O desirable city! Your walls are a single stone, your guardian will be God, your citizens will always be glad, since they enjoy forever the vision of God. There is no corruption in you, or defect, or old age or anger—but perennial peace, unchanging glory, eternal joy, continual celebration. Truly there is only joy and exultation, the flower and confidence of youth and of complete salvation. In you there is neither yesterday nor past, but all is today, since yesterday is your tomorrow and the past is everlasting and the same. Health is in you, life is in you, to you belongs infinite peace, and for you God is everything. "Of you they say marvelous things, O city of God." "All make their dwelling in you with joy." In you there is no fear or sadness. Every desire is turned into joy, since everything that can be desired is within reach, and everything one could want is there in abundance. All your inhabitants will receive a full measure of happiness, so that all might visibly rejoice together, without end. All will rejoice together, because the brothers and sisters will live together when all will gather in a single place. Finally, all will be one, as he who was worthy of his prayer being heard deigned to pray for his family, "As you, Father, are in me and I in you, may they also be one in us."