147:12-14 Verse 12 introduces a third round of praise (cf. vv. 1, 7). The psalmist called on the Israelites to praise God because He had brought security, stability, peace and prosperity to Jerusalem again.
147:15-20 Verses 15-18 describe the powerful effect God's commands have on creation (cf. vv. 4, 8-9). God also sent His Word to Israel (vv. 19-20; cf. vv. 2-3, 6, 11). This was a unique blessing since it involved a revelation of His gracious will. God's people should praise Him in view of all these things.
"It has been well pointed out that, purely as the means of getting things done, statutes and ordinances, or even appeals and encouragements, are most uncertain tools. So by addressing us, not programming us, God shows that He seeks a relationship, not simply a sequence of actions carried out."209
God's greatness as seen in His control over nature and His graciousness as seen in His dealings with His people call for praise. God sustains both the creation and His creatures with His Word.
(NT only) to listen to the NET Bible 
