A thought from Kotzk:[1]
The main thing that was remarkable in Avraham’s action was that even after three days he was still consumed with excitement to do G-d’s will.
For, while many people can attain the level of complete self-sacrifice for a moment, only Avraham was able to retain this feeling for three days—though he had time to contemplate his actions.
[1] Emet Mkotzk Titzmach, Pg. 118