Some Points in the Beatitudes
Our holy Saviour applied poverty and riches, and the like, both to spiritual things and objects of sense. For when He said, “Blessed are they that are persecuted for righteousness' sake,” He clearly taught us in every circumstance to seek for the martyr who, if poor for righteousness' sake, witnesses that the righteousness which he loves is a good thing; and if he “hunger and thirst for righteousness' sake,” testifies that righteousness is the best thing. Likewise he, that weeps and mourns for righteousness' sake, testifies to the best law that it is beautiful.
As, then, “those that are persecuted,” so also “those that hunger and thirst” for righteousness' sake, are called “blessed” by Him who approves of the true desire, which not even famine can put a stop to. And if “they hunger after righteousness itself,” they are blessed. “And blessed are the poor,” whether “in spirit” or in circumstance— that is, if for righteousness' sake. It is not the poor simply, but those that have wished to become poor for righteousness' sake, that He pronounces blessed— those who have despised the honours of this world in order to attain “the good;” likewise also those who, through chastity, have become comely in person and character, and those who are of noble birth, and honourable, having through righteousness attained to adoption, and therefore “have received power to become the sons of God,” and “to tread on serpents and scorpions,” and to rule over demons and “the host of the adversary.” And, in fine, the Lord's discipline draws the soul away gladly from the body, even if it wrench itself away in its removal.
“For he that loves his life shall lose it, and he that loses his life shall find it,” if we only join that which is mortal of us with the immortality of God. It is the will of God [that we should attain] the knowledge of God, which is the communication of immortality. He therefore, who, in accordance with the word of repentance, knows his life to be sinful will lose it— losing it from sin, from which it is wrenched; but losing it, will find it, according to the obedience which lives again to faith, but dies to sin. This, then, is what it is “to find one's life,” “to know one's self.”
Source: The Stromata, or Miscellanies (New Advent)