Who are God’s children?

I would have thought this would be an easy question.  Who are God's children?

Apparently not so easy.  At least not for some -

Baptist Pastors Won’t Hear Ben Carson after Young Pastors Object

That the answer to this question isn't "all of us" raises a couple interesting questions.  

Which of us are not God's children?
Whose children are we?

The "problem"

This has to do with Dr. Ben Carson, who will probably run for president, speaking at the Southern Baptist Pastors Conference in June.

Before getting into the problem, I'd like to draw attention to one statement that was made -

“We are concerned because in our evangelical climate it is often easy to confuse what it means to be a follower of Christ with what it means to be a patriotic American,” the blog read.

I completely agree with this one.  I'd suggest that maybe nothing else even needed to be said.  

But they went further.

“Certainly, we do not all worship the same God—we worship the Trinity whom Muslims and Jews would deny,” leaders of Baptist21 wrote on their blog. “And, the idea that we are all God’s children is at best the type of liberalism the Conservative Resurgence sought to address, and at worst, it is universalism.”

This gives the appearance that the real reason for preventing Dr. Carson from speaking at the conference has more to do with his particular beliefs than with the fact that he's going to run for president.  If that's the case, then I think there's cause for concern.

Problem #1

Certainly, we do not all worship the same God...

I think one needs to be careful with this one.  Saying that Jews don't worship the same God as Christians is maybe going too far?  

Wasn't Jesus Himself a Jew?  

Jn 4:9 The Samaritan woman said to him, “You are a Jew and I am a Samaritan woman. How can you ask me for a drink?” (For Jews do not associate with Samaritans.)

Even the Samaritan woman at the well knew that Jesus was Jewish.  If being Jewish is a starting point for not being a child of God - whose child is Jesus?

Didn't David talk about God's Spirit?

Ps 51:10 Create in me a pure heart, O God,
and renew a steadfast spirit within me.
Ps 51:11 Do not cast me from your presence
or take your Holy Spirit from me.
Ps 51:12 Restore to me the joy of your salvation
and grant me a willing spirit, to sustain me.

David didn't talk about "The Trinity" in those words - but neither does the New Testament.

Was David not a child of God?

And for those who have read pretty much any of my posts in the "Islam - Peace, Love and Hope" section have seen plenty of evidence related to God's promises to Abraham, Hagar and yes, Ishmael.  Would god make promises like this one -

Ge 17:19 Then God said, “Yes, but your wife Sarah will bear you a son, and you will call him Isaac. I will establish my covenant with him as an everlasting covenant for his descendants after him. 20 And as for Ishmael, I have heard you: I will surely bless him; I will make him fruitful and will greatly increase his numbers. He will be the father of twelve rulers, and I will make him into a great nation. 21 But my covenant I will establish with Isaac, whom Sarah will bear to you by this time next year.” 22 When he had finished speaking with Abraham, God went up from him.

- if Ishmael was not a child of God?
And if Ishmael wasn't a son of God - then to whose child were these promises made by God?  Not to mention, why?

As much as some might not like it, I also have to point out this, from the conclusion of Jonah -

Jonah’s Anger at the LORD'S COMPASSION