Will you be rewarded for not killing any one, or will you be rewarded for all the people you could have killed but did not?
Your question reveals you do not understand this commandment. You are distorting this commandment exactly as did the Pharisees and that is precisely why your view of sin and righteousness is Phariseeical.
Christ taught that this commandment is actually violated when unjust anger is allowed in your heart. So in order to obey this command, you must prevent unjust anger from arising, occuring in your heart.
Hence, the proper question should be, does God reward you for preventing unjust anger from arising in your heart, which is obedience to this commandment?
You see, properly understanding the commandment changes the whole nature of your two questions does it not? Your questions would have to be worded as followed:
Will you be rewarded for refusing to allow unjust anger at anyone, or will you be rewarded for all the people you could have been unjustly angry with but did not get angry at?
When you word it properly then your attempt to make a distinction simply vanishes because obedience to your first question is required to obey the second question because it all comes down to RESTRAINING anger from arising in your heart period whether potentially or actually!
So, why can't you get yourself to ask the question in keeping with how God will view it on Judgement day? Will God reward obedience to His commandments on judgement day and will he view them as "good works" or does he view obedience to his commandments as "bad works"?
Moriah, there is only two possible responses to his commandments!
1. Obedience
2. Disobedience
Moriah, on judgement day there are only two possible classifications for reward and they correspond exactly to whether you OBEYED or DISOBEYED his commandments. He will either reward you according to what he deems as GOOD works or EVIL works.
So Moriah, is restraining unjust anger from arising in your heart DISOBEDIENCE or OBEDIENCE to this command?
So Moriah, does God view OBEDIENCE as "good works" or as "evil works"??
So Moriah, does God REWARD obedience?
BTW Moriah, how do YOU prevent unjust anger from arising in your heart?