Because there are these two periods of time – the one that now is, beset with the trials and troubles of this life, and the other yet to come, a life of everlasting serenity and joy – we are given two liturgical seasons, one before Easter and the other after. The season before Easter signifies the troubles in which we live here and now, while the time after Easter which we are celebrating at present signifies the happiness that will be ours in the future. What we commemorate before Easter is what we experience in this life; what we celebrate after Easter points to something we do not yet possess. This is why we keep the first season with fasting and prayer; but now the fast is over and we devote the present season to praise. Such is the meaning of the Alleluia we sing.

Both these periods are represented and demonstrated for us in Christ our head. The Lord’s passion depicts for us our present life of trial – shows how we must suffer and be afflicted and finally die. The Lord’s resurrection and glorification show us the life that will be given to us in the future.

Now therefore, brethren, we urge you to praise God. That is what we are all telling each other when we say Alleluia. You say to your neighbor, “Praise the Lord!” and he says the same to you. We are all urging one another to praise the Lord, and all thereby doing what each of us urges the other to do. But see that your praise comes from your whole being; in other words, see that you praise God not with your lips and voices alone, but with your minds, your lives and all your actions.

St. Augustine of Hippo