Note the contradiction in the following two verses, discussing the selection of a successor High Priest.
• Verse Lv16-32 states And the priest,
  • whom he shall anoint,
  • and whom he shall consecrate
  • to minister in the priest’s office
  • to replace his father,
  shall make the atonement, and shall put on the linen clothes, the holy garments;
• Verse Lv21-10 states And he who is the high priest
  • among his brothers,
  • upon whose head the anointing oil was poured,
  • and who is consecrated to put on the garments,
  shall not uncover his head, nor tear his clothes;

We see the contradiction, indicated by the underlined words. Which is it? Is the successor priest his son or a colleague from among his brothers?

Rashi resolves this contradiction using the method of two aspects:
• If the current High-Priest's son is worthy then this son takes preference (is first candidate) in being considered for a high priest (even if someone else is equally qualified);
• If the current High-Priest's son is not worthy then the most worthy and qualified priest is selected as successor High-Priest

Sermonic Points: Judaism is frequently maligned by our enemies as being a tribal religion where authority is inherited. This is not so. Judaism is filled with people who rose to the top despite their lack of social placement: Moses and David were youngest not eldest; Ahaliav who built the temple was not from a preferred tribe; Ephraim and Menasheh were made into full Jewish tribes even though they were not children of Jacob. So too with the priesthood. We always want the most qualified and worthy person for high-priest. But if the son of the current priest is equally qualified then he is chosen. Here we see a delicate but meaningful blending of tribal and by-merit methods.