Rejoice in the Lord, O ye just; praise becometh the upright (Ps. 32:1).
The voice of exultation is familar in the Scripture, betokening a very bright and happy state of soul in those deserving of happiness.
‘Rejoice,’ therefore, ‘in the Lord, O ye just,’ not when the interests of your home are flourishing, not when you are in good health of body, not when your fields are filled with all sorts of fruits, but, when you have the Lord – such immeasurable Beauty, Goodness, Wisdom.
Let the joy that is in Him suffice for you. He who exults with joy and happiness in anything that is much desired, seems thus to rejoice in Him.
Therefore, Scripture urges the just to be aware of their dignity, because they have been considered worthy to be the servants of so great a Master, and to glory in His service with inexpressible joy and exultation, since the heart is, as it were, bounding with ecstasy of love of the good.
If at any time a light, for example, falling upon your heart, produced a continuous thought of God and illumined your soul, so that you loved God and despised the world and all things corporeal, understand from that faint and brief resemblance the whole state of the just, who are enjoying God steadily and uninterruptedly.
At some rare times by the dispensation of God that transport of joy seizes you in order that through a little taste He may remind you of what you have been deprived. But, for the just man the divine and heavenly joy is lasting, since the Holy Spirit dwells in him once for all.
‘But the firstfruit of the Spirit is: charity, joy, peace’ (Gal. 5:22). Therefore, ‘rejoice in the Lord, O ye just.’ The Lord is like a place capable of containing the just, and there is every reason for one who is in Him to be delighted and to make merry.
Moreover, the just man becomes a place for the Lord, when he receives Him in himself. He who sins gives place to the devil, taking no heed of him who said: ‘Do not give place to the devil’ (Eph. 4:27), nor to Ecclesiastes, ‘If the spirit of him that hath power, ascend upon thee, leave not thy place’ (Eccles. 10:4).
Let us, then, who are in the Lord and who, as much as we are able, observe closely His wonders, so draw joy to our hearts from the contemplation of them.
Basil the Great (330-379): Homily 15 (on Psalm 32), 1, from Saint Basil: Exegetic Homilies, translated by Agnes Clare Way, Catholic University of America Press (The Fathers of the Church, vol. 46), pp. 227-228.