Happy is that people, that is (n) in such a case: yea, happy is that people, whose God is the LORD.

(n) And if God does not give to all his children all these blessings, yet he replaces them with better things.

Matthew Henry's Concise Commentary

144:9-15 Fresh favours call for fresh returns of thanks; we must praise God for the mercies we hope for by his promise, as well as those we have received by his providence. To be saved from the hurtful sword, or from wasting sickness, without deliverance from the dominion of sin and the wrath to come, is but a small advantage. The public prosperity David desired for his people, is stated. It adds much to the comfort and happiness of parents in this world, to see their children likely to do well. To see them as plants, not as weeds, not as thorns; to see them as plants growing, not withered and blasted; to see them likely to bring forth fruit unto God in their day; to see them in their youth growing strong in the Spirit. Plenty is to be desired, that we may be thankful to God, generous to our friends, and charitable to the poor; otherwise, what profit is it to have our garners full? Also, uninterrupted peace. War brings abundance of mischiefs, whether it be to attack others or to defend ourselves. And in proportion as we do not adhere to the worship and service of God, we cease to be a happy people. The subjects of the Saviour, the Son of David, share the blessings of his authority and victories, and are happy because they have the Lord for their God.