We are invited, no encouraged to pray "Thy Kingdom Come."
In light of this I want to introduce you to 3 words.
1. Parousia - it means presence or arrival. When God returns or breaks through. When He comes in power, holding nothing back.
2. Epiphaneia - which is where we get the word epiphany from. It means appearing.
3. Apocalypse - in our time it has come to mean 'something terrible is about to happen.' But this wasn't what how it was understood in the 1st C. It simply meant unveiling.
Pulling back the curtain. Lifting the cover.
So praying God's Kingdom Come simply means we are asking God to "break through from hiddenness".