3:13-18 Among the Jews at this time, some plainly discovered themselves to be children of the wicked one. The yoke of Christ is easy. But those who work wickedness, tempt God by presumptuous sins. Judge of things as they will appear when the doom of these proud sinners comes to be executed. Those that feared the Lord, spake kindly, for preserving and promoting mutual love, when sin thus abounded. They spake one to another, in the language of those that fear the Lord, and think on his name. As evil communications corrupt good minds and manners, so good communications confirm them. A book of remembrance was written before God. He will take care that his children perish not with those that believe not. They shall be vessels of mercy and honour, when the rest are made vessels of wrath and dishonour. The saints are God's jewels; they are dear to him. He will preserve them as his jewels, when the earth is burned up like dross. Those who now own God for theirs, he will then own for his. It is our duty to serve God with the disposition of children; and he will not have his children trained up in idleness; they must do him service from a principle of love. Even God's children stand in need of sparing mercy. All are righteous or wicked, such as serve God, or such as serve him not: all are going to heaven or to hell. We are often deceived in our opinions concerning both the one and the other; but at the bar of Christ, every man's character will be known. As to ourselves, we have need to think among which we shall have our lot; and, as to others, we must judge nothing before the time. But in the end all the world will confess that those alone were wise and happy, who served the Lord and trusted in Him.
14. what profit … that we … kept, &c.—(See on Mal 2:17). They here resume the same murmur against God. Job 21:14, 15; 22:17 describe a further stage of the same skeptical spirit, when the skeptic has actually ceased to keep God's service. Ps 73:1-14 describes the temptation to a like feeling in the saint when seeing the really godly suffer and the ungodly prosper in worldly goods now. The Jews here mistake utterly the nature of God's service, converting it into a mercenary bargain; they attended to outward observances, not from love to God, but in the hope of being well paid for in outward prosperity; when this was withheld, they charged God with being unjust, forgetting alike that God requires very different motives from theirs to accompany outward observances, and that God rewards even the true worshipper not so much in this life, as in the life to come.
his ordinance—literally, what He requires to be kept, "His observances."
walked mournfully—in mournful garb, sackcloth and ashes, the emblems of penitence; they forget Isa 58:3-8, where God, by showing what is true fasting, similarly rebukes those who then also said, Wherefore have we fasted and Thou seest not? &c. They mistook the outward show for real humiliation.