Objection 1. It would seem that man's happiness consists in glory. For happiness seems to consist in that which is paid to the saints for the trials they have undergone in the world. But this is glory: for the Apostle says (Romans 8:18): "The sufferings of this time are not worthy to be compared with the glory to come, that shall be revealed in us." Therefore happiness consists in glory.
Objection 2. Further, good is diffusive of itself, as stated by Dionysius (Div. Nom. iv). But man's good is spread abroad in the knowledge of others by glory more than by anything else: since, according to Ambrose [Augustine, Contra Maxim. Arian. ii. 13, glory consists "in being well known and praised." Therefore man's happiness consists in glory.
Objection 3. Further, happiness is the most enduring good. Now this seems to be fame or glory; because by this men attain to eternity after a fashion. Hence Boethius says (De Consol. ii): "You seem to beget unto yourselves eternity, when you think of your fame in future time." Therefore man's happiness consists in fame or glory.
On the contrary, Happiness is man's true good. But it happens that fame or glory is false: for as Boethius says (De Consol. iii), "many owe their renown to the lying reports spread among the people. Can anything be more shameful? For those who receive false fame, must needs blush at their own praise." Therefore man's happiness does not consist in fame or glory.
I answer that, Man's happiness cannot consist in human fame or glory. For glory consists "in being well known and praised," as Ambrose [Augustine, Contra Maxim. Arian. ii, 13 says. Now the thing known is related to human knowledge otherwise than to God's knowledge: for human knowledge is caused by the things known, whereas God's knowledge is the cause of the things known. Wherefore the perfection of human good, which is called happiness, cannot be caused by human knowledge: but rather human knowledge of another's happiness proceeds from, and, in a fashion, is caused by, human happiness itself, inchoate or perfect. Consequently man's happiness cannot consist in fame or glory. On the other hand, man's good depends on God's knowledge as its cause. And therefore man's beatitude depends, as on its cause, on the glory which man has with God; according to Psalm 90:15-16: "I will deliver him, and I will glorify him; I will fill him with length of days, and I will show him my salvation."
Furthermore, we must observe that human knowledge often fails, especially in contingent singulars, such as are human acts. For this reason human glory is frequently deceptive. But since God cannot be deceived, His glory is always true; hence it is written (2 Corinthians 10:18): "He... is approved... whom God commendeth."
Reply to Objection 1. The Apostle speaks, then, not of the glory which is with men, but of the glory which is from God, with His Angels. Hence it is written (Mark 8:38): "The Son of Man shall confess him in the glory of His Father, before His angels" [St. Thomas joins Mark 8:38 with Luke 12:8 owing to a possible variant in his text, or to the fact that he was quoting from memory].
Reply to Objection 2. A man's good which, through fame or glory, is in the knowledge of many, if this knowledge be true, must needs be derived from good existing in the man himself: and hence it presupposes perfect or inchoate happiness. But if the knowledge be false, it does not harmonize with the thing: and thus good does not exist in him who is looked upon as famous. Hence it follows that fame can nowise make man happy.
Reply to Objection 3. Fame has no stability; in fact, it is easily ruined by false report. And if sometimes it endures, this is by accident. But happiness endures of itself, and for ever.
Source: Summa Theologica (New Advent)