A person desperately searching for a way to please God often imagines that grand gestures are the answer. This search is expressed through a series of rhetorical questions that gradually escalate, moving from massive quantities of standard offerings to the unthinkable extreme of human sacrifice.
The search begins by asking if God would be pleased and accepting [מצודת ציון] of thousands of choice rams, which are considered a premium sacrifice [רד״ק, מלבי״ם]. The offers quickly multiply, asking if God desires tens of thousands of rivers of oil. This oil would normally be poured over meal offerings [רש״י, מצודת דוד] or used as libations for burnt offerings [מלבי״ם]. Naturally, these massive quantities are completely unrealistic. They are intentional exaggerations meant to sharpen the point that physical abundance alone cannot satisfy the Creator [רד״ק].
When the realization sets in that no amount of animals or oil is enough, the speaker moves to the most extreme proposal imaginable. He asks if he must give up his beloved firstborn son as a sacrifice to atone for his severe crimes [רש״י, רד״ק, אבן עזרא]. He then broadens this extreme proposal to include his other offspring [מצודת ציון], particularly the children he loves most dearly [רד״ק], offering them to cleanse his soul of its sins.
The primary approach among commentators is that these questions represent a desperate attempt to please God and earn forgiveness. However, another perspective suggests that the speaker is not looking for atonement at all. Instead, he is wondering what possible gift he could offer God as a reward or token of gratitude after God has already forgiven his crimes [מצודת דוד].
Within these extreme offers, there is a precise connection between the severity of the sin and the proposed sacrifice. Intentional rebellion requires the ultimate price, which is why the speaker suggests offering his firstborn son. On the other hand, lighter sins committed by mistake or driven by physical desire are matched with the offer of the younger children [מלבי״ם].
Ultimately, these escalating questions lead to a profound realization: a person possesses no physical object that can truly satisfy his Creator [אבן עזרא]. God does not want endless burnt offerings, countless rivers of oil, and certainly not human sacrifices acting as a substitute for genuine, internal repair [ביאור שטיינזלץ].