G-d or Yitzchak

Earlier in the Parshah, G-d told Avraham that He was going to destroy Sedom. Most people would have not questioned G-d's plan-but Avraham did. He asked G-d if he could find 10 righteous people in Sedom then would He still destroy Sedom. G-d said that He wouldn't. Avraham could not and Sedom was eventually destroyed. The main point here is that Avraham stood up to G-d and told Him that he didn't think His plan was moral or just. Then a while later G-d tells Avraham to kill his son, Yitzchak. Avraham says nothing, and carries out G-d's orders (until the angel stops him). Why doesn't Avraham say anything to G-d? Why does he not stand up to G-d like he did before? Clearly this order is not moral or just. G-d is asking Avraham to kill the most precious person in his life (with the exception of Sarah). Avraham finally has his descendent that will be part of G-d's promise. Avraham had to wait decades for a child then kick out his first-born. Yitzchak is finally born and G-d tells him that he will be the Zera that Avraham had been waiting for. Now, G-d is telling Avraham to sacrifice him. And Avraham says nothing.

Of course, one could say that in the case of Sedom, Avraham was not given direct orders from G-d like he is during the time of the Akaidah story; therefore, he was allowed to disagree with G-d's plan. He is not allowed to question direct orders even if it means going against his own moral code.

Personally, I think Avraham has gained the right to disagree with G-d's orders on a few occasions after all that he's done. He should not have had to go through with the Akaidah. He has already shown full faith in G-d and has even spent his life teaching others about G-d. He should not have to choose between jepardizing his relationship with G-d and his son/Zera.