Deuteronomy 33:9

Who said to his father, &c., I have not seen him That is, I have no respect unto them in comparison of God and my duty. The meaning is, Who followed God and his command fully, and executed the judgment enjoined without any respect of persons. It appears to refer to the whole tribe of Levi, who, fired with a holy zeal for God and his worship, performed impartial execution on the worshippers of the golden calf, not excepting even their nearest relations that were concerned in that wickedness: see Exodus 32:26. They kept thy covenant When the rest broke their covenant with God by the foul sin of idolatry, that tribe kept themselves pure from that infection, and adhered to God and his worship. Some also include herein their impartiality in the administration of justice, that they had not accepted, nor should accept the persons of any, not even their relations. To which we may add that the office of the priests and Levites, which engaged their constant attendance, at least by turns, at God's altar, laid them under a necessity of being frequently absent from their families, which they could neither take such care of nor make such provision for, as other Israelites might. This constant self-denial they submitted to, that they might observe God's word, and keep the covenant of priesthood. And all those, even under the gospel, who are called to minister in holy things, should remember that it is their duty to sit loose to the relations and interests which are dearest to them in this world, and prefer the fulfilling of their ministry before the gratifying the best friend they have, Acts 20:24; Acts 21:13. Our Lord Jesus knew not his mother and his brethren, when they would have taken him from his work, Matthew 12:48.