Job 12:20

"He changes the lips of his faithful servants. He changes them for good so that they may rest, not on their holiness, but on their grace. "He knows the experience of old people. He likes it. Whence this word: "You are known to God (1); And this other, quite the opposite, "I do not know you." This is how he wisely leads us from faith to the experience of the aged.

"By changing the speech of those who speak truly." He is not referring here to those who speak truly, so much as to those who believe they speak truly. He convinces them of their falsehood when he makes what they had predicted happen in a different way."By taking away the doctrine of the elders," Job shows them that the frustration of their projects occurs without any consideration for their authority. "He pours contempt on princes," both those who are entrusted with teaching and the leaders who take care of the administration of common goods. When God opposes them, they lose completely the high position they previously had where they stood. "He lifts up those who were oppressed." After showing what God can do to these people, who are considered to be illustrious, he includes the wealth and protection he can grant to the humble, so that the divine power may be known by both these classes of people.

Who changeth the lip of the truthful, and taketh away the instruction of the aged. When the priest does not do the good that he tells, even the very word of his lips is withdrawn from him, that he may not dare to speak what he does not practise; as where it is said by the Prophet, But unto the wicked God saith, 'What hast thou to do, to declare My statutes, or that thou takest My covenant in thy mouth? Whence also he beseeches, saying, And take not the word of truth utterly out of my mouth. For he reflects that Almighty God gives the word of truth to those that do it, and takes it away from those that do it not. He then that prayed that he might not have it 'taken out of his mouth,' what did he else than pray for the grace of good practice? As if he said in plain words, 'Let me not go astray from good works, lest, while I lose the regularity of good living, I also part with the right rule of speaking.' And for the most part the teacher, who ventures to teach what he neglects to practise, when he ceases to speak the good which he scorned to do, begins to teach his charge the evil things that he does, that, by the righteous judgment of the Almighty, that man may not henceforth have a tongue for a good theme, who will not have a good life; so that whilst his mind is inflamed with the love of earthly things, he should be ever speaking of earthly things. Whence 'Truth' saith in the Gospel, For out of the abundance of the heart the mouth speaketh. A good man out of the good treasure of the heart bringeth forth good things, and an evil man out of the evil treasure bringeth forth evil things. Hence also John saith, They are of the world, therefore speak they of the world. Therefore it is well said, Who changeth the lip of the truthful, and taketh away the instruction of the aged. In that while they, who were aforetime 'truthful' in preaching heavenly things, setting their affections on those of time, are sunk down to the same, 'the lip of the truthful is changed, and the instruction of the aged taken away;' in that being in love with temporal things, they never follow the precepts of their predecessors, so as to be occupying the place of authority as if but for the fruit of pleasure, and for no good end of labour. Which nevertheless may be understood more plainly of the Jews, who before the Lord's Incarnation were 'truthful,' in that they believed that He was to…