1)
Why did the angel call Avraham's name twice?
1.
Rashi: Calling someone twice by name is a sign of love. 1
2.
Chazon Yechezkel: Once someone decided how to act, it is very hard to change. Therefore, the command to refrain had to be said more forcefully.
1
Refer to 6:9:151:1, refer to Shemos 3:4:151:1.