The mystery of God (Revelation 10:7).
The mysteries of the kingdom of heaven.
The riches of the glory of the mystery.
The only true God is an eternal mystery.
He is so glorious, so wonderful, so powerful – and infinitely, eternally more – He is beyond human comprehension.
Knowing Him is an eternal revelation.
Those who find Him and make it to heaven will be in awe of Him, forever.
He is indescribable, incomprehensible, unfathomable.
He is all-knowing, all-powerful, everywhere.
He is life, love, eternity and infinitely more.
He is holy.
He will be beyond human words, forever.
Yet, He has revealed Himself.
He is no longer a mystery.
He is no longer a secret.
He is available.
He is a present reality.
The only true God, the infinite, eternal mystery, can be summed up in one word: Jesus.

The mystery is . . . the only true God . . . Jehovah God Almighty and His Son the Lord Jesus Christ, in the power of the Holy Spirit.
The deepest reality of knowing Him is . . .
Fellowship with God through His Son Jesus Christ through the Holy Spirit . . .
Someone may ask, what is God like? What is Jesus Christ like? What is the Holy Spirit like?
He is the most wonderful, most beautiful Person in the universe.