Your word have I hid in my heart, that I might not sin against you.
Read Chapter 119
George Leo Haydock
Heart. To guard against the temptations of vanity. (Calmet)
Christians formerly concealed the mysteries of religion with the utmost care. (St. Hilary and St. Ambrose)
Moses had given the letter of the law only, insinuating, that it must be kept with all the heart, as David here more fully explains. (Berthier)