Doesn't need to be explained by anything else. God fits the bill. That's why belief in God is justified. Science can tell us what the fundamental laws of nature are , but it can't explain why the universe follows them. God lacks no perfection.
Existence is a perfection.
That's why belief in God is justified. I have everything to gain, and very little to lose, by believing in God. It's in my best interest to believe in God. Sometimes I simply can't help but believe in God. In these cases, even though I can't articulate an argument for why God exists, I still have a right to believe.