Till/until kingdom come old-fashioned informal
In a way that lasts for a long time or for all time in the future
I am willing to wait for you till kingdom come.
These students will be expelled from the school until kingdom come.
Permanently or finally
Forever.
1. Used to indicate something lasts forever
2. Said when you believe something will never happen
If you do something “till you are blue in the face”, you do it with many efforts but receive no or less success.
It is believed to have originated from Biblical cited the line "thy kingdom come" from the Lord's Prayer.