C. F. Keil and Franz Delitzsch on Proverbs 18:11

Pro 18:11 11 The possession of the righteous is his strong fort,      And is like a high wall in his imagination.

Line first = Pro 10:15. משׂכּית from שׂכה, Chald. סכה(whence after Megilla 14a, יסכּה, she who looks), R. שׂך, cogn. זך, to pierce, to fix, means the image as a medal, and thus also intellectually: image (conception, and particularly the imagination) of the heart (Psa 73:7), here the fancy, conceit; Fleischer compares (Arab.) tṣwwr, to imagine something to oneself, French se figurer. Translators from the lxx to Luther incorrectly think on שׂכך (סכך), to entertain; only the Venet. is correct in the rendering: ἐν φαντασίᾳ αὐτοῦ; better than Kimchi, who, after Ezr 8:12, thinks on the chamber where the riches delighted in are treasured, and where he fancies himself in the midst of his treasures as if surrounded by an inaccessible wall.

We place together Pro 18:12-19, in which the figure of a secure fortress returns: