Musar על סוטה 9:14

Our Rabbis said: "Every man who is impudent or proud of spirit it is as though he were an idolator" (Sotah 4b), for it is written, "Every one that is proud in heart is an abomination to the Lord" (Prov. 16:5) and it is written there: "You must not bring an abhorrent thing (idol) into your house …" (Deut. 7:26). And there are those who say it is as though he violated all the laws against sexual license, for it is written: "For all these abominations were done by the people who were in the land before you and the land became defiled …" (Lev. 18:27). And there are those who say, "It is as though he built a place for idolatry." And they said in Sotah 5a, "Every man who is arrogant of spirit becomes less in the end as it is said: 'They are exalted for a little while' (Job 24:25). And such a one is deserving to be hewn down like a grove planted for idol worship, as it is said: 'And the high ones of stature shall be hewn down' (Is. 10:33). And his dust shall not awaken and the Spirit of God laments over him. The Holy One Blessed be He, said, 'I and he cannot live in the same world,' as it is said: 'Whoso is haughty of eye and proud of heart, him will I not suffer'" (Ps. 101:5).

We have an allusion to this in Psalms 131. David testifies that though he had certainly attained a measure of understanding about the ways of G–d, this had not been a cause for him to become proud or haughty. In this Psalm the words לא גבה לבי allude to the שלימות הגוף, whereas the following words ולא רמו עיני allude to the שלימות הממון, seeing that it is the eye which is usually the cause of greed for money. The last words ולא הלכתי בגדולות refer to the שלימות הנפש. It means that David did not seek out merits which were beyond his ability to achieve, and when he was granted them he did not boast about such achievements. When our sages report that any halachic ruling made by David was always accepted as final this may have been the reward for his humility.