John Trapp on Psalms 37:31

Verſ. 31. The law of his God is in his heart] He hath a Bible in his head, and another in his heart; he hath a good treaſure within, and therehence bringeth good things; he ſpeaketh not by rote, and as a bungler, or as a Philoſopher only; but by proof, and as one that can ſay, I beleeved, I have felt it, and therefore have I ſpoken.

None of his ſteps ſhall ſlide] How ſhould they, when they walk ſo exactly, and by ſuch a rule? Jeremy holding to it, durſt ſay, Lord if I am deceived, thou haſt deceived mee.