But, while I am conversing with you about the first evening of the world, evening takes me by surprise, and puts an end to my discourse. May the Father of the true light, Who has adorned day with celestial light, Who has made the fire to shine which illuminates us during the night, Who reserves for us in the peace of a future age a spiritual and everlasting light, enlighten your hearts in the knowledge of truth, keep you from stumbling, and grant that “you may walk honestly as in the day.” Thus shall you shine as the sun in the midst of the glory of the saints, and I shall glory in you in the day of Christ, to Whom belong all glory and power for ever and ever. Amen.
Source: Nine Homilies of Hexaemeron (New Advent)