Happy is the man - Hebrew, The happiness of the man. See the notes at Psalms 1:1.
That hath his quiver full of them - The quiver is a case in which arrows are carried; and as a man - a hunter or warrior - feels secure when he has his quiver full of arrows, so a man is blessed in proportion to the number of his sons. This is in accordance with the idea often presented in the Bible, and the promise often made there of a numerous posterity as a proof of the divine favor.
They shall not be ashamed - They shall not turn back discomfited, hanging their heads with shame and confusion. See the notes at Job 6:20.
But they shall speak with the enemies in the gate - Margin, “shall subdue, or destroy.” The Hebrew word, however, means “to speak;” and the meaning is, that they would “speak” to their foes in the place of conflict - for a battle occurred often in the gate of a city, as the possession of a gate, or an entrance to a city was of so much importance to those who attacked, and those who defended it. The idea is, that they would speak with effect; they would distinguish themselves; they would let their presence be known. The connection does not allow us to understand this of forensic controversy, or of transactions in business, though these were usually performed at the gates of cities. The meaning is, that they would do honor to the family, and gratify the heart of the parent, by their valor in defending their city and home, or in attacking the cities of the enemies of their country. The psalm is designed to inculcate the lesson of dependence on God for success in everything.