Firstly, it doesn't matter that Abraham did not kill his son. What mattered was Abraham's willingness, which God praised him for.
Secondly, you state Moses and the other prophets killed because the people who deserved it were deemed harmful to society. Given that Christians frequently say homosexuality will destroy society, why aren't Christians stoning homosexuals to death (as the Bible commands)?
It
does matter that God didn't allow Abraham to kill his son, because that shows the character of God and what His true intentions were. Abraham had the nerve to doubt God when He said He would give Sarah a son, and Sarah even laughed at God. This allowed Abraham to make up for that, showing that he trusts God above all else, even when what He says doesn't make sense.
As for why I wouldn't stone homosexuals to death, for one, it's against the law. Second, Christians are commanded to love everyone, even the people who flog and kill them. It would be kind of hard to spread the Gospel while you're throwing a rock at someone.
How do you know this for certain? For that matter, Christians seem to to blindly believe that the prophets in the Bible all knew they were hearing from God. Yet my own experience at church showed me that most Christians get it wrong when they believe God is speaking to them. They act on what they believe is God, and find out later that they made a terrible mistake, or something goes wrong, etc. Furthermore, the vast number of Christian denominations is probably good evidence that Christians, these days, just aren't hearing from God AT ALL.
I've been to one of those churches where everyone thought they were prophets. The fact that they got it wrong is a sign that they can't hear from God. If they could, they would be right. When Abraham heard from God, the message came true. It doesn't hurt that He showed up in the form of an angel, either, or that his wife could also see God and the two angels that were with him. Sometimes, God is kind of hard to ignore. Who could miss a burning bush that had a voice coming from it? Or a flash of light that physically blinds you and speaks to you, and which was also experienced by the people around you?
That kind of thing never happened to me. I get the more subtle stuff. I'm not a prophet. We have the Bible to consult for God's word today.
For someone to believe they are hearing from God does not necessitate that they are mentally ill. Also, consider that George W Bush believed he heard from God who told him to go to war against Iraq. Would you say Bush was mentally ill? I'd say he was probably stupid, but not mentally ill. Bush was convinced (or so he claims) that he heard from God.
Did he really believe that, or was he just saying what he thought would win him points with the voters? Remember, he's a politician, not the pope.
God himself is a contradictory character. Compare the NT with the early parts of the OT (Genesis to Joshua) and you'll see two different sides to God that contrast with each other. Jesus is full of mercy and grace, whereas Yahweh is a jealous and angry God.
If God does actually talk to people, given his seemingly erratic nature, it would be hard to tell just what message is coming across. God likes to play both good cop and bad cop at the same time it seems.
I'll say what I've always said when this argument came up. There is no difference between the OT and NT God. The God of the OT shows mercy to the repentant sinner, and He is slow to show His wrath. The NT God killed a man and his wife for lying and trying to make themselves look good and spiritual. God shows mercy and love in both halves of the Bible, and He shows His wrath is both halves of the Bible.
Similarly, Jesus healed the masses, but He also drove our the businessmen from the temple in righteous anger. Jesus is God, so of course He's going to have the same qualities as the Father.
Also, I'd just like everyone to know (for anyone interested in the poll on this thread) that it wasn't me who voted yes (there's currently 1 yes vote at the time of writing). I haven't read through all the thread yet, so I don't know who voted yes. It may well be an atheist trolling the thread via the poll, or it may be Christian. Either way, I'm not going to judge. Whoever voted yes, it's a matter for their own conscience.
^^^Probably him. I haven't voted, since there is neither answer is full enough to express my views.
This is one of your better observations. Now, to confront how in the world this can be righteous? Also: compare to "He shall Baptize you with the Holy Ghost, and with fire."
And you call this petty? I mean, what was a Prophet's role in those days again? I do credit you for getting the point of this Scripture. what about the Prophet who was told to marry a harlot? Why? And how'd that turn out? 
