Objection 1. It would seem that joy is not an effect of devotion. As stated above (3, ad 2), Christ's Passion is the chief incentive to devotion.
But the consideration thereof causes an affliction of the soul, according to Lamentations 3:19, "Remember my poverty... the wormwood and the gall," which refers to the Passion, and afterwards (Lamentations 3:20) it is said: "I will be mindful and remember, and my soul shall languish within me." Therefore delight or joy is not the effect of devotion.
Objection 2. Further, devotion consists chiefly in an interior sacrifice of the spirit. But it is written (Psalm 50:19): "A sacrifice to God is an afflicted spirit." Therefore affliction is the effect of devotion rather than gladness or joy.
Objection 3. Further, Gregory of Nyssa says (De Homine xii) [Orat. funebr. de Placilla Imp.] that "just as laughter proceeds from joy, so tears and groans are signs of sorrow." But devotion makes some people shed tears. Therefore gladness or joy is not the effect of devotion.
On the contrary, We say in the Collect [Thursday after fourth Sunday of Lent]: "That we who are punished by fasting may be comforted by a holy devotion."
I answer that, The direct and principal effect of devotion is the spiritual joy of the mind, though sorrow is its secondary and indirect effect. For it has been stated (3) that devotion is caused by a twofold consideration: chiefly by the consideration of God's goodness, because this consideration belongs to the term, as it were, of the movement of the will in surrendering itself to God, and the direct result of this consideration is joy, according to Psalm 76:4, "I remembered God, and was delighted"; but accidentally this consideration causes a certain sorrow in those who do not yet enjoy God fully, according to Psalm 41:3, "My soul hath thirsted after the strong living God," and afterwards it is said (Psalm 41:4): "My tears have been my bread," etc. Secondarily devotion is caused as stated (3), by the consideration of one's own failings; for this consideration regards the term from which man withdraws by the movement of his devout will, in that he trusts not in himself, but subjects himself to God. This consideration has an opposite tendency to the first: for it is of a nature to cause sorrow directly (when one thinks over one's own failings), and joy accidentally, namely, through hope of the Divine assistance. It is accordingly evident that the first and direct effect of devotion is joy, while the secondary and accidental effect is that "sorrow which is according to God" [2 Corinthians 7:10.
Reply to Objection 1. In the consideration of Christ's Passion there is something that causes sorrow, namely, the human defect, the removal of which made it necessary for Christ to suffer [Luke 24:25; and there is something that causes joy, namely, God's loving-kindness to us in giving us such a deliverance.
Reply to Objection 2. The spirit which on the one hand is afflicted on account of the defects of the present life, on the other hand is rejoiced, by the consideration of God's goodness, and by the hope of the Divine help.
Reply to Objection 3. Tears are caused not only through sorrow, but also through a certain tenderness of the affections, especially when one considers something that gives joy mixed with pain. Thus men are wont to shed tears through a sentiment of piety, when they recover their children or dear friends, whom they thought to have lost. On this way tears arise from devotion.
Source: Summa Theologica (New Advent)