I suggest that you read through Augustine’s explanation of time. In book Eleven of his Confessions, Augustine goes through a detailed analysis and pondering of the question of time, and if the past, present, and future exist.
Even though it is called “Book Eleven”, it is actually more like just a chapter of Confessions, and what it calls “chapters” are for the most part little more than a paragraph or a few each, so overall it is a relatively short read:
Some of the things he ponders and explains are:
"…There was no time, therefore, when thou hadst not made anything, because thou hadst made time itself. And there are no times that are coeternal with thee, because thou dost abide forever; but if times should abide, they would not be times.
For what is time? Who can easily and briefly explain it? Who can even comprehend it in thought or put the answer into words? Yet is it not true that in conversation we refer to nothing more familiarly or knowingly than time? And surely we understand it when we speak of it; we understand it also when we hear another speak of it.
What, then, is time? If no one asks me, I know what it is. If I wish to explain it to him who asks me, I do not know. Yet I say with confidence that I know that if nothing passed away, there would be no past time; and if nothing were still coming, there would be no future time; and if there were nothing at all, there would be no present time.
But, then, how is it that there are the two times, past and future, when even the past is now no longer and the future is now not yet? But if the present were always present, and did not pass into past time, it obviously would not be time but eternity. If, then, time present – if it be time – comes into existence only because it passes into time past, how can we say that even this is, since the cause of its being is that it will cease to be? Thus, can we not truly say that time is only as it tends toward non-being?"