A literal translation of the Hebrew would be holy seed.
The use of this phrase echoes what we read in Deuteronomy 7:6. The focus of this concept is not on genetics (racial purity) but a living relationship between Israel and God (see Exodus 19:6; Leviticus 19:2).1 The people of Israel have been set apart as holy to the Lord and they must maintain religious purity, not polluting themselves by following the practices of the nations around them.
2 For they have taken some of their daughters to be wives for themselves and for their sons, so that the holy race has mixed itself with the peoples of the lands. And in this faithlessness the hand of the officials and chief men has been foremost.”