David [was] thirty years old when he began reign
Over Judah, which was the age of his antitype Christ, when he entered upon his public ministry, ( Luke 3:23 ) ;
[and] he reigned forty years;
and six months, as appears by ( 2 Samuel 5:5 ) ; but the months are not mentioned, only the round number of years given: two reasons the Jews F1 give for this; the one, that he fled six months from Absalom; the other is, that he was ill in Hebron so long, and therefore are not reckoned.
F1 Hieron. Trad. Heb. in lib. Reg. fol. 77. I.