Verse 1
Psalms 127:1. Except the Lord build the house — That is, assist and bless those that build it, whether an artificial house, such as the temple, or the royal palace, or any of those numerous structures which Solomon raised; or rather, a natural or civil house, a family or kingdom; they labour in vain that build it — They will never succeed well in their attempts, bring it to perfection, or have any comfort in it. The success of all our undertakings depends so entirely upon God’s blessing, that it is in vain to attempt any thing without it: in vain is it to build houses and cities, or to endeavour to uphold families, or establish states, unless he prosper the design: and the care of the watchman, of the soldier, or magistrate, is to no purpose, unless the divine providence be likewise the guard. “In every undertaking the blessing of God must accompany the labours of man to render them effectual. No work can prosper without him; nor can any design miscarry under his favour and protection. Above all men they ought to implore the divine grace and benediction, who are employed either in building or defending the spiritual house and city of God; especially as the same persons, like the Jews after the captivity, surrounded by enemies, always ready to obstruct the work, are often obliged to hold a sword in one hand while they build with the other. Our own edification in faith and holiness must likewise be carried on by us in this attitude, by reason of the many temptations which are continually assailing us.” — Horne.


Verse 2
Psalms 127:2. It is vain for you — Builders or watch-men, or other persons engaged in any design, which to you seems important; to rise up early, to sit up late — To use constant and unwearied diligence; to eat the bread of sorrows — Or, the bread of fatigue, as some render it; to labour hard, and fare poorly. For so — By his blessing, and not singly by industry without it; or, as the word כןis rendered in the margin, certainly, or since, as Dr. Hammond translates it; he giveth his beloved sleep — His people, who, though hated and maligned by men, are beloved of God, and over whom his providence watcheth in a special manner. He gives them quiet rest, both of body and mind, and that freely, without that immoderate toiling and drudgery wherewith others pursue it. Observe, reader, the psalmist does not intend to say that labour and diligence are vain, but that they are so unless the Lord be with and bless the labourer: the business is not to be done by all the industry and pains, all the care and labour in the world, without him; whereas, if his aid be called in, if part of our time be spent in prayer, and not the whole of it in prayerless care and labour, our work will become easier and go on better: a solicitude and anxiety for its success and completion will no longer prey upon our minds by day, and break our rest at night; we shall cheerfully fulfil our daily tasks, and then, with confidence and resignation, lay our heads upon our pillows, and God will give us sweet and undisturbed sleep, which shall fit us to return every morning with renewed vigour and alacrity to our stated employments: see Horne.

Verse 3
Psalms 127:3. Lo, children are a heritage of the Lord — They come not from the power of mere nature, but from God’s blessing, even as an inheritance is not the fruit of a man’s own labour, but the gift of God. He can, in a moment, blast the most fruitful stock, or he can make the barren woman keep house, and become a joyful mother of children. The psalmist mentions children here, because all the forementioned toil and labour are, in a great measure, and most commonly, undertaken for their sakes; and because they are the chief of all those blessings to which he refers. And the fruit of the womb is his reward — Not a reward of debt, merited by good men, but a reward of grace, as the apostle expresses himself, Romans 4:4, which God gives them graciously, as Jacob acknowledges of his children, Genesis 35:5. God indeed frequently gives children, and other outward comforts, to ungodly men, but this is in the way of his common providence; whereas he gives them to his people as peculiar favours, and in the way of promise and covenant.


Verse 4-5
Psalms 127:4-5. As arrows are in the hand of a mighty man — That knows how to use them for his own safety and advantage; so are children of the youth — Children born to their parents when they are young, who are generally the strongest and most healthful children, grow up, and become qualified to serve their parents by the time they need their service, and who live longest with them; whereas those who are born in old age seldom arrive at mature age before their parents die. Such children, when well educated, pious, and obedient, are like so many arrows in the hand of a mighty man, “ready winged with duty and love to fly to the mark; polished and keen to grace and maintain the cause of their parents, to defend them from hostile invasions, and instantly to repel every assailant.” Happy is he who hath his quiver full of them — Whose house is as full of children as the quiver of a mighty man is of arrows. They — These parents, who have such a numerous issue; shall not be ashamed, &c. — Shall courageously plead their cause in courts of judicature, which were held at the gates of cities, not fearing to be crushed by the might of their adversaries, as weak and helpless persons frequently are. Or, as some understand the words, the children shall not be ashamed to plead for their parents in the gates, but will be ready at all times to appear for them, to answer any charge that may be brought against them and to vindicate them in their persons, their good name, or their property.