1....We are not Christians, except on account of a future life: let no one hope for present blessings, let no one promise himself the happiness of the world, because he is a Christian: but let him use the happiness he has, as he may, in what manner he may, when he may, as far as he may. When it is present, let him give thanks for the consolation of God: when it is wanting, let him give thanks to the Divine justice. Let him always be grateful, never ungrateful: let him be grateful to his Father, who soothes and caresses him: and grateful to his Father when He chastens him with the scourge, and teaches him: for He ever loves, whether He caress or threaten: and let him say what you have heard in the Psalm: “It is a good thing to give thanks unto the Lord; and to sing praises unto Your Name, Thou Most Highest”.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)