1. Parents bless their children in the name of the Lord several ways:
(1.) By instruction; the discharge whereof was the glory and honor of Abraham in the sight of God himself, Genesis 18:17-19. For whereas the knowledge and fear of God are the greatest blessing that any one in this world can be made partaker of, he hath ordained that parents shall be instrumental in the communication of them unto their children; suitably unto that general law of nature whereby they are obliged in all things to seek their good. This being the end of the instruction which God hath appointed them to attend unto, they do therein bless them in the name of the Lord. And if parents did truly consider how they stand in the stead of God in this matter, how what they do is peculiarly in his name and by his authority, they would, it may be, be more diligent and conscientious in the discharge of their duty than they are. And if children could but understand that parental instruction is an instituted means of God’s blessing them with the principal blessing, and that whereon all others, as unto them, do much depend, — whereunto the fifth commandment is express, — they would with more diligence and reverence apply themselves unto the reception of it than is usual among them.
(2.) They do it by their example. The conversation and holy walking of parents is God’s ordinance whereby he blesseth their children. This is the second way of instruction, without which the former will be insufficient, yea, insignificant. Let parents take what pains they please in the teaching and instructing of their families, unless their personal walk be holy, and their lives fruitful, they will do more for their destruction than their edification. The least disorder of life persisted in, is of more prevalency to turn aside children from the ways of God, from the liking and practice of them, than a multitude of instructions are to persuade to their embracement. For, besides that we are all naturally more prone to evil than good, and a far less occasion or means will hasten us down a precipice than raise us and bear us up in the difficult course of holy obedience, instances of a life inconsistent with instructions, or not answering them, beget secret thoughts in the minds of them who are instructed that all the pains taken therein are hypocritical; than which apprehension nothing is more effectual to alienate the minds of any from the ways of God. But when men’s teachings of their families are exemplified by the holiness and fruitfulness of their own lives, then are they an ordinance of God for the blessing of them. To pray, to read, to catechise, to instruct, and then to lead a life of frowardness, passion, worldly-mindedness, vain communication, and the like, is to pull down with one hand what we set up with the other; or rather, with both our hands to pull down our own houses.
(3.) By prayer for them. So David blessed his household, 2 Samuel 6:20. For besides the duty of prayer absolutely considered, there is in those prayers, by the appointment of God, an especial plea for and application of the promises of the covenant unto them which we ourselves have received. So it is expressed in the prayer of David, 2 Samuel 7:29. “Therefore now let it please thee to bless the house of thy servant, that it may continue for ever before thee: for thou, O Lord GOD, hast spoken it: and with thy blessing let the house of thy servant be blessed for ever.” And I do not understand how those who do not believe in the especial interest of their children in the covenant of grace, can bless them in the name of the Lord in a due manner. These are some few heads of parental benediction; which whether the duty thereof be answered in that common custom which some even confine all parental blessings unto, in an open neglect of all the duties mentioned, and others of an alike nature, is not hard to determine.
– John Owen from exposition of Hebrews chapter 7