Moreover by them is your servant warned: and in keeping of them there is great reward.
All Commentaries on Psalms 19:11 Go To Psalms 19
Augustine of Hippo
AD 430
12. "For Thy servant keepeth them "(ver. 11). For to him who keepeth them not the day of the Lord is bitter. "In keeping them there is great reward." Not in any external benefit, but in the thing itself, that God's judgments are kept, is there great reward; great because one rejoiceth therein.