It’s the differential between the frequency of consciousness and the frequency of the level of reality being viewed.
When the two approach the same frequency, time stands still.
And then it’s time to tune into a new reality, like Heaven.
Time being a measurement of the rate of change of physical THINGS (current most accurate being vibration frequencies of some isotopes - ‘atomic clock’), means that time is bound to the natural world.
For those things outside the natural world, time is not applicable.
Fun part of that is that time is finite - it had a beginning, and it has an end. There is no change to measure without this.