10 And yet, Brethren, our God never can be poor. He is rich, He made all things, heaven and earth, the sea and Angels. In the heaven, whatsoever we see, whatsoever we see not, He made it. But notwithstanding, we ought not to love these riches, but Him who made them. For He has promised you nothing but Himself. Find anything more precious, and He will give you this. Beauteous is the earth, the heaven, and the Angels; but more beauteous is He who made them. They then who preach God, as loving God; who preach God, for God's sake, feed the sheep, and are no hirelings. This chastity did our Lord Jesus Christ require of the soul, when He said to Peter, “Peter, do you love Me”? What is “Do you love Me”? Are you chaste? Is not your heart adulterous? Do you seek not your own things in the Church, but Mine? If then you be such an one, and lovest Me, “feed My sheep.” For you shall be no hireling, but you shall be a shepherd.
Source: Sermons on Selected Lessons of the New Testament (New Advent)