Objection 1. It seems that the desire of glory is not a sin. For no one sins in being likened to God: in fact we are commanded (Ephesians 5:1): "Be ye... followers of God, as most dear children." Now by seeking glory man seems to imitate God, Who seeks glory from men: wherefore it is written (Isaiah 43:6-7): "Bring My sons from afar, and My daughters from the ends of the earth. And every one that calleth on My name, I have created him for My glory." Therefore the desire for glory is not a sin.
Objection 2. Further, that which incites a mar to do good is apparently not a sin. Now the desire of glory incites men to do good. For Tully says (De Tusc. Quaest. i) that "glory inflames every man to strive his utmost": and in Holy Writ glory is promised for good works, according to Romans 2:7: "To them, indeed, who according to patience in good work... glory and honor" [Vulgate: 'Who will render to every man according to his works, to them indeed who... seek glory and honor and incorruption, eternal life.']. Therefore the desire for glory is not a sin.
Objection 3. Further, Tully says (De Invent. Rhet. ii) that glory is "consistent good report about a person, together with praise": and this comes to the same as what Augustine says (Contra Maximin. iii), viz. that glory is, "as it were, clear knowledge with praise." Now it is no sin to desire praiseworthy renown: indeed, it seems itself to call for praise, according to Sirach 41:15, "Take care of a good name," and Romans 12:17, "Providing good things not only in the sight of God, but also in the sight of all men." Therefore the desire of vainglory is not a sin.
On the contrary, Augustine says (De Civ. Dei v): "He is better advised who acknowledges that even the love of praise is sinful."
I answer that, Glory signifies a certain clarity, wherefore Augustine says (Tract. lxxxii, c, cxiv in Joan.) that to be "glorified is the same as to be clarified." Now clarity and comeliness imply a certain display: wherefore the word glory properly denotes the display of something as regards its seeming comely in the sight of men, whether it be a bodily or a spiritual good. Since, however, that which is clear simply can be seen by many, and by those who are far away, it follows that the word glory properly denotes that somebody's good is known and approved by many, according to the saying of Sallust (Catilin.) [The quotation is from Livy: Hist., Lib. XXII C, 39: "I must not boast while I am addressing one man].
But if we take the word glory in a broader sense, it not only consists in the knowledge of many, but also in the knowledge of few, or of one, or of oneself alone, as when one considers one's own good as being worthy of praise. Now it is not a sin to know and approve one's own good: for it is written (1 Corinthians 2:12): "Now we have received not the spirit of this world, but the Spirit that is of God that we may know the things that are given us from God." Likewise it is not a sin to be willing to approve one's own good works: for it is written (Matthew 5:16): "Let your light shine before men." Hence the desire for glory does not, of itself, denote a sin: but the desire for empty or vain glory denotes a sin: for it is sinful to desire anything vain, according to Psalm 4:3, "Why do you love vanity, and seek after lying?"
Now glory may be called vain in three ways. First, on the part of the thing for which one seeks glory: as when a man seeks glory for that which is unworthy of glory, for instance when he seeks it for something frail and perishable: secondly, on the part of him from whom he seeks glory, for instance a man whose judgment is uncertain: thirdly, on the part of the man himself who seeks glory, for that he does not refer the desire of his own glory to a due end, such as God's honor, or the spiritual welfare of his neighbor.
Reply to Objection 1. As Augustine says on John 13:13, "You call Me Master and Lord; and you say well" (Tract. lviii in Joan.): "Self-complacency is fraught with danger of one who has to beware of pride. But He Who is above all, however much He may praise Himself, does not uplift Himself. For knowledge of God is our need, not His: nor does any man know Him unless he be taught of Him Who knows." It is therefore evident that God seeks glory, not for His own sake, but for ours. On like manner a man may rightly seek his own glory for the good of others, according to Matthew 5:16, "That they may see your good works, and glorify your Father Who is in heaven."
Reply to Objection 2. That which we receive from God is not vain but true glory: it is this glory that is promised as a reward for good works, and of which it is written (2 Corinthians 10:17-18): "He that glorieth let him glory in the Lord, for not he who commendeth himself is approved, but he whom God commendeth." It is true that some are heartened to do works of virtue, through desire for human glory, as also through the desire for other earthly goods. Yet he is not truly virtuous who does virtuous deeds for the sake of human glory, as Augustine proves (De Civ. Dei v).
Reply to Objection 3. It is requisite for man's perfection that he should know himself; but not that he should be known by others, wherefore it is not to be desired in itself. It may, however, be desired as being useful for something, either in order that God may be glorified by men, or that men may become better by reason of the good they know to be in another man, or in order that man, knowing by the testimony of others' praise the good which is in him, may himself strive to persevere therein and to become better. On this sense it is praiseworthy that a man should "take care of his good name," and that he should "provide good things in the sight of God and men": but not that he should take an empty pleasure in human praise.
Source: Summa Theologica (New Advent)