15 “In the power of an horse He will not take pleasure”. The power “of an horse” is pride. For the horse seems adapted as it were to bear a man aloft, that he may be more uplifted as he goes. And in truth he has a neck which typifies a sort of pride. Let not men exalt themselves upon their worth, let them not think themselves uplifted by their distinctions; let them beware lest they be thrown by an untamed horse....“Nor in the tabernacle of a man will He delight.” For the tabernacle of the Lord is the Holy Church spread throughout the whole world. Heretics, separating themselves from the Church's tabernacles, have set up tabernacles for themselves. For if perchance it be the lot of any, who is good and pious, who confesses his own weakness, who is “the young of a raven that calls on God,” not to enjoy worldly distinction, he goes not out of the Church, he sets not up for himself a tent outside the Church, wherein God will not delight. But what says he? “I have chosen to be cast away in the house of God, rather than to dwell in the tents of sinners.”
Source: The Enarrations, or Expositions, on the Psalms (New Advent)