Exodus 32 – Skeptic's Annotated Bible answered

1 And when the people saw that Moses delayed to come down out of the mount, the people gathered themselves together unto Aaron, and said unto him, Up, make us gods, which shall go before us; for as for this Moses, the man that brought us up out of the land of Egypt, we wot not what is become of him.

(32:1-35) Aaron's golden calf
"Aaron said to them, Break off the golden earrings, which are in the ears of your wives, of your sons, and of your daughters, and bring them unto me ... And ... he had made it a molten calf."
Aaron makes a golden calf and tells the people to take off their clothes and dance around naked. God then punishes them mercilessly for following their divinely appointed religious leader.

2 And Aaron said unto them, Break off the golden earrings, which are in the ears of your wives, of your sons, and of your daughters, and bring them unto me.

3 And all the people brake off the golden earrings which were in their ears, and brought them unto Aaron.

4 And he received them at their hand, and fashioned it with a graving tool, after he had made it a molten calf: and they said, These be thy gods, O Israel, which brought thee up out of the land of Egypt.

5 And when Aaron saw it, he built an altar before it; and Aaron made proclamation, and said, To morrow is a feast to the LORD.

6 And they rose up early on the morrow, and offered burnt offerings, and brought peace offerings; and the people sat down to eat and to drink, and rose up to play.

7 And the LORD said unto Moses, Go, get thee down; for thy people, which thou broughtest out of the land of Egypt, have corrupted themselves:

8 They have turned aside quickly out of the way which I commanded them: they have made them a molten calf, and have worshipped it, and have sacrificed thereunto, and said, These be thy gods, O Israel, which have brought thee up out of the land of Egypt.

9 And the LORD said unto Moses, I have seen this people, and, behold, it is a stiffnecked people:

10 Now therefore let me alone, that my wrath may wax hot against them, and that I may consume them: and I will make of thee a great nation.

(32:10) "Let me alone, that my wrath may wax hot against them, and that I may consume them."

11 And Moses besought the LORD his God, and said, LORD, why doth thy wrath wax hot against thy people, which thou hast brought forth out of the land of Egypt with great power, and with a mighty hand?

(32:11-13) "And Moses besought the LORD ... repent of this evil against thy people."
Moses talks God out of killing all the Israelites.

12 Wherefore should the Egyptians speak, and say, For mischief did he bring them out, to slay them in the mountains, and to consume them from the face of the earth? Turn from thy fierce wrath, and repent of this evil against thy people.

13 Remember Abraham, Isaac, and Israel, thy servants, to whom thou swarest by thine own self, and saidst unto them, I will multiply your seed as the stars of heaven, and all this land that I have spoken of will I give unto your seed, and they shall inherit it for ever.

14 And the LORD repented of the evil which he thought to do unto his people.

(32:14) "And the Lord repented of the evil which he though to do unto his people."
But how could a good God even consider doing evil to anyone? And how could an unchangeable God change his mind? 
Does God repent?

15 And Moses turned, and went down from the mount, and the two tables of the testimony were in his hand: the tables were written on both their sides; on the one side and on the other were they written.

16 And the tables were the work of God, and the writing was the writing of God, graven upon the tables.

17 And when Joshua heard the noise of the people as they shouted, he said unto Moses, There is a noise of war in the camp.

18 And he said, It is not the voice of them that shout for mastery, neither is it the voice of them that cry for being overcome: but the noise of them that sing do I hear.

19 And it came to pass, as soon as he came nigh unto the camp, that he saw the calf, and the dancing: and Moses’ anger waxed hot, and he cast the tables out of his hands, and brake them beneath the mount.

(32:19-21, 31) "He saw ... the dancing: and Moses' anger waxed hot."
Is dancing a sin?

20 And he took the calf which they had made, and burnt it in the fire, and ground it to powder, and strawed it upon the water, and made the children of Israel drink of it.

(32:20) "He ... made the children of Israel drink of it."
Moses burned the golden calf, ground it into powder, and then forced it down the throats of all the people.

21 And Moses said unto Aaron, What did this people unto thee, that thou hast brought so great a sin upon them?

22 And Aaron said, Let not the anger of my lord wax hot: thou knowest the people, that they are set on mischief.

23 For they said unto me, Make us gods, which shall go before us: for as for this Moses, the man that brought us up out of the land of Egypt, we wot not what is become of him.

24 And I said unto them, Whosoever hath any gold, let them break it off. So they gave it me: then I cast it into the fire, and there came out this calf.

(32:24) "I cast it into the fire, and there came out this calf."
Aaron just threw the gold earrings into the fire and (Presto!) out came a golden calf!

25 And when Moses saw that the people were naked; (for Aaron had made them naked unto their shame among their enemies:)

(32:25) "For Aaron had made them naked."
Aaron makes the people take off all their clothes and dance naked around his golden calf.

26 Then Moses stood in the gate of the camp, and said, Who is on the LORD’S side? let him come unto me. And all the sons of Levi gathered themselves together unto him.

(32:26) "Who is on the Lord's side?"
To be on the Lord's side you must be willing to kill your family and friends for God.

27 And he said unto them, Thus saith the LORD God of Israel, Put every man his sword by his side, and go in and out from gate to gate throughout the camp, and slay every man his brother, and every man his companion, and every man his neighbour.

(32:27-28) "Thus saith the LORD God of Israel, Put every man his sword by his side, and go in and out from gate to gate throughout the camp, and slay every man his brother, and every man his companion, and every man his neighbour."
God has the people kill each other for dancing naked around Aaron's golden calf.
God tells the sons of Levi (Moses, Aaron, and the other members of their tribe that were "on the Lord's side") to kill their family and friends for dancing naked around Aaron's golden calf. "And there fell of the people that day about 3000 men."
God's 11th Killing
To kill or not to kill.

28 And the children of Levi did according to the word of Moses: and there fell of the people that day about three thousand men.

29 For Moses had said, Consecrate yourselves to day to the LORD, even every man upon his son, and upon his brother; that he may bestow upon you a blessing this day.

30 And it came to pass on the morrow, that Moses said unto the people, Ye have sinned a great sin: and now I will go up unto the LORD; peradventure I shall make an atonement for your sin.

Yahweh Relents

31 And Moses returned unto the LORD, and said, Oh, this people have sinned a great sin, and have made them gods of gold.

32 Yet now, if thou wilt forgive their sin--; and if not, blot me, I pray thee, out of thy book which thou hast written.

33 And the LORD said unto Moses, Whosoever hath sinned against me, him will I blot out of my book.

(32:33) "Whosoever hath sinned against me, him will I blot out of my book."

34 Therefore now go, lead the people unto the place of which I have spoken unto thee: behold, mine Angel shall go before thee: nevertheless in the day when I visit I will visit their sin upon them.

35 And the LORD plagued the people, because they made the calf, which Aaron made.

(32:35) "The Lord plagued the people, because of the calf, which Aaron made."
God wasn't satisfied with the slaughter of the 3000, so he killed some more people with a plague.
God's 12th Killing