For they intended evil against thee: they imagined a mischievous device, which they are not able to perform.
David could have given thanks to God in private, but he testified publicly that whatever blessings God conferred upon him redounded to the common good of all His people. Yet above all, the Holy Spirit directs our minds here to Christ, who was the end and perfection of this kingdom, teaching us we cannot be saved except under the Head God Himself appointed.
AI summary
Commenting on Psalm 21:1-13
"For they intended evil against thee." God takes notice of intentions. He who would but could not is as guilty as he who did. Christ's church and cause are not only attacked by those who do not understand it, but there are many who have the light and yet hate it.
The psalmist, having taught his people to look back with joy and praise on what God had done for him and them, here teaches them to look forward with faith, and hope, and prayer, upon what God would further do for them: The king rejoices in God (Psa 21:1), and therefore we will be thankful; the king trusteth in God (Psa 21:7), therefore will we be encouraged.
Commenting on Psalm 21:7-13