Deuteronomy 33:9

9 He said of his father and mother, ‘I have no regard for them.’ He did not recognize his brothers or acknowledge his own children, but he watched over your word and guarded your covenant.

Read Deuteronomy 33:9 Using Other Translations

Who said unto his father and to his mother, I have not seen him; neither did he acknowledge his brethren, nor knew his own children: for they have observed thy word, and kept thy covenant.
who said of his father and mother, 'I regard them not'; he disowned his brothers and ignored his children. For they observed your word and kept your covenant.
The Levites obeyed your word and guarded your covenant. They were more loyal to you than to their own parents. They ignored their relatives and did not acknowledge their own children.