The relationship between God and His people rests on the basic, everyday foundations of family and authority. Common sense tells us that a son naturally respects his father, and a servant fears his master [רד״ק, אבן עזרא, צאינה וראינה]. Against this backdrop, a sharp rebuke is directed at the nation's leaders for their profound ingratitude. There is a core difference between the two relationships presented here: love versus fear. A son honors his father out of a genuine, internal desire and love, reflecting the love the father gives him [מצודת דוד, אברבנאל]. A servant, however, obeys out of necessity and a fear of consequences [מלבי״ם]. Because the Israelites are considered both sons and servants to God [רש״י], He challenges them on both fronts. If He is their father, where is the honor born of love? And if He is their master, and they lack love, where is at least the basic fear of punishment? [מלבי״ם, אברבנאל].
The imagery of the son and the servant is also seen as a historical reference to other nations. Esau was known as a son who showed great respect for his father, while Ishmael was considered a servant, being the son of a maidservant. God argues that if these nations knew how to properly honor their fathers and masters, the Israelites certainly should have known how to honor their Creator. Because of this failure, the merit of their ancestors will not protect them now [אהבת יהונתן, נחל שורק].
This criticism is not aimed at the general public, but zeroes in on the priests. During the Second Temple period, the sacrifices were the primary remaining center of holiness. As the leaders of the people, the teachers of the Torah, and those closest to God, the priests were expected to guard this sacred service [אברבנאל]. Instead of correcting the people and guiding them properly, they enabled bad behavior and allowed disgraceful sacrifices to be brought to the altar [רד״ק].
Anticipating their reaction, God notes that the priests will play innocent and ask how they have shown disrespect [רש״י]. Because they continued to serve in the Temple and maintain the outward rules, they genuinely did not understand where they went wrong [ביאור שטיינזלץ]. Yet, their very question reveals the depth of their spiritual blindness; not only are they doing wrong, but they completely deny it and refuse to admit any guilt [אברבנאל]. The reality of their offense is that they are offering defective animals, handling the rituals in a way that repels the human soul, and ultimately turning God's sacred table into something cheap and despised [מצודת דוד, צאינה וראינה].