Suppose that we accept a 'pop' Einsteinian idea of Time as sequential and linear but going at relatively different speeds in different places and conditions - as a consequence of the speed of light being fixed.
But let us also suppose that there is an underlying, absolute, objective Time behind all of this - which is due to there being a God for whom Time is also sequential: Divine Time is therefore the objective reality underpinning the different relative speeds of Time in different places.
Anyway... Let us assume that from the perspective of our earthly and mortal life, Time in Heaven can run at different speeds than here.
Heavenly Time must run such as to achieve incomprehensibly more in a single second of earthly time than possible on earth, or else the vast work of creating and sustaining the earth and its denizens could not be accomplished.
From earth this would look as if the denizens of Heaven were operating in a blur of activity; from Heaven it would seem that hardly anything happens on earth.
But also, it seems likely that Heavenly Time could also be very slowed-up and almost suspended relative to earth-time; so that it would seem from earth that perhaps a Heavenly inhabitant was living in a frozen state of suspended animation.
In sum - let us say that Time in Heaven might run very much faster or slower than earthly time, as seen from an earthly perspective.
(This seems necessary for Heaven to accomplish what Heaven accomplishes.)
But this seems to create a serious problem of communication between Heaven and earth - because it is presumably extremely difficult and unsatisfactory to communicate with those whose Time may be either vastly sped-up or slowed-down - the relative rate of their activities is so different - what would seem like rapid interaction to one party would seem unbearably/ uselessly delayed to the other party - or, in reverse.
And the primary communication is of course Love.
It is hard to imagine Love between entities living at grossly different Time speeds - and this perhaps creates a problem for God the Father in his relationship with his earthly children?
God the Father must always be creating and sustaining the universe - which presumably involves unimaginably numerous and rapid activities (as they would seem to us).
Thus, the fastest possible Time is objective Time - God's Time.
Therefore, it is a vital part of Christian life to synchronize earth and Heaven - in practice this comes by a signal sent from here on earth in response to which a Heavenly entity will synchronize Time with us (usually by Heaven slowing-down a lot!).
For example, an angelic being who is whizzing around doing things (say) a billionfold faster than possible on earth, get a message and slows down and matches Time-speed with the earthly inhabitant who has signaled that communication is requested.
Then, having communicated, the angel speeds-up again to Heavenly Time. Or else the gaps are bridged by a hierarchy of angels living at different rates of Time.
What are these signals from earth - these requests to synchronize Time?
Perhaps things such as prayer, meditation, Liturgy, Holy Communion, Temple Ordinances and the like - perhaps these can be imagined as a signal for Heaven to match speed with us and thereby open the channels of communication?
(For example, perhaps Baptism of the Dead could be imagined to work by creating a synchronization of Time between the living and a post-mortal spirit, to slowdown the life of the spirit, and bring the post-mortal spirit into communication with the living; so the spirit can perceive the love expressed towards him or her. Perhaps otherwise, the spirit would be living either so rapidly and busily - or else so slowly and inertly - as to be incapable of exercising autonomous choice? By signalling to the spirit, getting the spirit to slow-down to mortal speed, and creating a state of communion with that post-mortal spirit; then the spirit is much better able to exercise agency and decide whether or not to accept the Gospel - than would be possible if earthly and Heavenly Time were grossly discrepant.)
Perhaps, furthermore, the rate of Time in earthly mortal life is optimal for making decisions about salvation and for accomplishing theosis.
Perhaps the acceptance of salvation, and working for theosis (and the highest exaltation) is not impossible in Heaven - but rather, it is very much more difficult and less likely, due to Heavenly Time being sub-optimal - usually too fast or too slow - and the efficacy of earthly prayers and rituals for the dead is related to getting post-mortal spirits at the right speed and into communication with us - who are the experts on salvation and theosis.
And, for God to do his infinite work of Love, required that Divinity synchronize Time with Men; hence God becoming Man - the incarnation of Christ and his dwelling among us on earth.
Perhaps the life of Christ can be seen as (to some partial extent) the ultimate act of synchronization of Time?