In spite of the fact that fools often pose the hazards of enmity, a God-fearing man who lacks intelligence is pre- ferable to a highly prudent man who transgresses the law (19:24), because a sage may play the role of an enemy. Certainly this is the case of a counselor who counsels in his own interest (37:7-9). That the sage may be an enemy is clearest, however, when Sirach's own era is the subject of the enemy behavior.
Whoever winks his eye plans evil deeds, and no one can keep him from them. In your presence his mouth is all sweetness, and he admires your words; but later he will twist his speech and with your own words he will give offense. I have hated many things, but none to be compared to him; even the Lord will hate him. Sirach 27:22-24
This enmity of the sage against one who winks his eye is not surprising, nor does it present any threat to the sage. The ego-enemy which Sirach fears most is not that of himself versus another, but rather that of himself versus himself. Fears of his own self-enmity are articulated only in prayer.
that a guard were set over my mouth,
and a seal of prudence upon my lips, that it may keep me from falling, so that my tongue may not destroy me!
Lord, Father and Ruler of my life, do not abandon me to their counsel, and let me not fall because of them!
that whips were set over my thoughts, and the discipline of wisdom over my mind!