Time is merely a measurement, but the fundamental dualistic
understanding of time is an illusion, that is, the assumption that
there are 'objects' persisting in time, separated and yet existing
in time.
Such time-object duality is ultimately illusory. Change exist, but
no changing thing. Ultimately there is no movement, because no
'objects' are moving, yet change is. When you understand this, you
will know that Time IS Existence, and Existence does NOT 'exist in
time'.
For a more deeper analysis of this subject for your contemplation,
please refer to
The Mahayana Deconstruction of Time
