As I read Exodus 32, there was something that I noticed that, perhaps, deserve some attention.  It concerns Moses pleading to God on behalf of Israel.  How did Moses manage to prevent God from consuming Israel?  (It is a marvelous show of grace on God's part that Moses actually gets to plead his case before God, but that's not the point right here.)  I think it has a lot to do with verse 13:

"Remember Abraham, Isaac, and Israel, your servants, to whom You swore by Your own self, and said to them, 'I will multiply your descendants as the stars of the heaven; and this land that I have spoken of I give to your descendants, and they shall inherit forever." - Exodus 32:13

God relents right after that in verse 14.  Maybe this isn't the only reason that God doesn't go ahead and execute His judgment, but nontheless it illustrates a point- God keeps covenant.  God honoured the covenant that He cut with Abraham way back in Genesis 15.  How much more will God honour the new covenant mentioned in Hebrews 8?  Let us have full assurance of faith that God is faithful to what He has promised.