At the height of divine anger over the sin of the Golden Calf, the fate of the Israelites hangs by a thread. God presents Moses with a dramatic alternative: the complete annihilation of the existing nation and the creation of a brand new one descending directly from Moses himself.
God begins by instructing Moses to step aside and withdraw his prayers [ביאור שטיינזלץ, בכור שור]. This request is not a physical push, but rather a direct command to stop pleading on their behalf [נתינה לגר]. However, a completely different intention hides behind this instruction. When the people sinned, Moses became weak and lost his ability to speak. By telling Moses to let go, God was actually hinting that the fate of the people rested entirely in his hands, providing him with the opening he needed to gather his strength and plead for mercy [תורה תמימה]. God was offering Moses a choice. He could surrender to despair over the severity of the sin, allowing the nation to be destroyed so he could take their place. Alternatively, he could choose to beg for their survival, offering himself as a ransom in their stead, which would lead to God's forgiveness [ביאור יש״ר]. Interestingly, Moses' actual response to this offer is not recorded at this moment [ביאור שטיינזלץ].
The threat hanging over the people was absolute. A basic decree of destruction might only imply the end of the current generation, but the divine intent to erase their very identity indicates the total loss of all their descendants, including the children [העמק דבר]. This total erasure was designed to prevent the other nations of the world from claiming that the greatness of Moses was built upon the ruins of the Israelites [קונטרס חיבה יתירה]. On a deeper level, this planned destruction was only meant for the physical world. The spiritual root of the Israelites would remain completely intact above. God intended to preserve this upper spiritual root and channel it back down into the world exclusively through Moses [נחל קדומים].
God concludes by promising to build Moses into a mighty and populous nation. Even though Moses ultimately prayed and successfully canceled the decree of destruction, this personal promise to him was still fulfilled. The primary approach among commentators is that any positive declaration from God, even if made with conditions, is never taken back. There is a fundamental difference between harsh judgments, which depend on human actions and can be reversed through repentance, and a divine promise for good, which is unconditional and permanent [תורה תמימה, נחלת יעקב]. As a result, even though the Israelites were saved, the descendants of Moses eventually multiplied to over six hundred thousand, fully realizing the promise to make him into a great nation [תורה תמימה].