> Why should anybody accept your God and (Christian) morality?

I'll start at God and then go to various quasi-religious systems, and finally Christianity. This'll be a bit long and not especially detailed, but hey, it is what it is.

First, why God rather than no God?

Fundamentally, there are only 2 possibilities. Platonism (broadly, to include Aristotle, the Stoics, etc.) says the world is fundamentally rational: comprehensible by intelligence.

The other option is the world is Heraclitean, & we are only in a bubble of local (apparent) order.

Now, it necessarily follows from the (broad) Platonic view that there is Being which grounds reality and is in some sense an Intelligence, since it makes intelligible.

So, if the world is intelligible, theism is the only live option.

Now, from theism, one has several options: philosophical/classical theism, Stoicism, revealed religions, shamanism/polytheism.

Now, any such world view / system must do two things:

1. Explain the totality of human experience.
2. Do so without distortion.

Mere philosophical theism does not properly answer the question of human suffering, nor does shamanism, although they both answer different desires of the human psyche: coherence and significance.

Stoicism promises much, but does not fulfill its promises often enough.

That leaves revealed religion. The revealed religions that are live options are: Christianity, Judaism, Islam, Sikhism.

Judaism and Islam seem to be too specific of law systems for certain peoples.

Sikhism seems to lack a full answer to human depravity.

That leaves Christianity, which offers an explanation of human depravity, human existence both as individual and community, as a creature with a spirit and a rational mind, and as a thing with an animal nature.

Thus, Christianity should be believed because it explains man.

Since it explains man, the morality that comes from that explanation is also correct, because it is in accord with both our nature in the Imago Dei and as fallen creatures.