Each year when it comes round, and we pray the collect for this day (Misericordias Domini), it strikes me as such a bold thing to ask of the Lord: "perpetual gladness and everlasting joy."
What does such a request mean? I think if we remember Psalm 16 (one of the great Easter psalms), we get a huge hint:
"You make known to me the path of life;
*in your presence* there is fullness of joy;
*at your right hand* there are pleasures forevermore."
As the people who have shared in Christ's paschal mystery and so through the grace of Holy Baptism been "rescued from the peril of everlasting death," we ask for unending joy, which is the exact same thing as to ask to live continually in the presence of God and in the place of His favor.
And when you stop and realize that this "bold" request is EXACTLY what the Blessed Trinity wants for us, and that to give it to us such unending joy is why our Lord took on flesh and surrendered that flesh to death, well, the joy starts welling up at the thought of it!
Our great Good Shepherd, who laid down His life for us, knows us and we know Him and He gives us eternal life and we shall never perish and no one shall snatch us out of His hand.
In the confidence of that, we cry together: "Grant to your faithful people, rescued from the peril of everlasting death, perpetual gladness and eternal joys!" Amen and Amen!