Moses a man carefully picked, 

God does not repent and if he has sent a word, it must fulfill His intention. God knew that Moses would make sure that His word comes to fulfilment. 

Imagine if I were the one God spoke to in Exodus 32:10, immediately i will be like Oya God destroy them and let's start with me😊

But Moses was pleading for them bringing to rememberance the promise to their fathers. 

Kia, truly Moses was a man faithful in his house