Your word is very pure: therefore your servant loves it.
Read Chapter 119
Augustine of Hippo
AD 430
138. Then considering with himself with what a flame of love he burned for the commandments of God: "Fiery," saith he, "is Thy word exceedingly, and Thy servant hath loved it" (ver. 140). Justly jealous was he of the impenitent heart in His enemies, who had forgotten God's word; for he endeavoured to bring them unto hat which he himself most ardently loved.
Refined. Literally, "fire. "(Haydock)
Pure as any thing which has passed through the fire. (Worthington)
"It consumes sin, and enlightens the penitent. "(St. Jerome)