The God of All

I have always heard questions like this: "if God is omnipotent, why does He allow the Devil to mess up everything He's done so far?" Why do He allow bad and not Good alone.

Now my first answer to that would be: God is the God of all. The same one created both. And thus it is written in the book of Isaiah 45: 7

I form the light, and create darkness: I make peace, and create evil: I the LORD do all these things

Jesus also when He was describing God as perfect used the words in Matthew 5:45

That ye may be the children of your Father which is in heaven: for he maketh his sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust.

Though it is hard or rare to think of God as even the God of the devil or angel. He owns the life and breathe of his enemies. He is God and creator of all. To saints and sinners, jew and gentiles, believers and atheist, christians and muslims, angels and demons, earth and skies, friends and enemies, everything that exists owe to him their life.
But this two parables would throw more light than much explanation would.

First is the parable of the field in Matthew 13 : 24 -30 (American Standard Version).

²⁴ Another parable set he before them, saying, The kingdom of heaven is likened unto a man that sowed good seed in his field:

²⁵ but while men slept, his enemy came and sowed tares also among the wheat, and went away.

²⁶ But when the blade sprang up and brought forth fruit, then appeared the tares also.

²⁷ And the servants of the householder came and said unto him, Sir, didst thou not sow good seed in thy field? whence then hath it tares?

²⁸ And he said unto them, An enemy hath done this. And the servants say unto him, Wilt thou then that we go and gather them up?

²⁹ But he saith, Nay; lest haply while ye gather up the tares, ye root up the wheat with them.

³⁰ Let both grow together until the harvest: and in the time of the harvest I will say to the reapers, Gather up first the tares, and bind them in bundles to burn them; but gather the wheat into my barn.

What about the enemy? Why didn't he just take out the enemy like the US took out Osama Bin Laden? Why wait for the enemy to cause much mess?
The answer is that firstly, to everything there is a time and a season to every purpose under the heaven. The 'taking out of the enemy' or his judgement would happen but not yet. Even the parable above illustrates this.

The next question is that until the taking out is done why not de-capitalize him, or disable his ability to cause more trouble?
The answer is so found in the bible , as in Romans 11:29 (Amplified Version)

For God's gifts and His call are irrevocable. [He never withdraws them when once they are given, and He does not change His mind about those to whom He gives His grace or to whom He sends His call.]

God so sticks to his laws and will not go against one. We can count on him on that. But incidentally we are all beneficiaries of this virtue because we all were one time enemies of God.