First of all, I respect everyone’s views, and I appreciate the thoughtful contributions from all participants.
Some members have said that I do not fully understand the meaning of atheism or the arguments commonly presented by atheists. With sincere humility, I would appreciate it if one of the brothers could explain these matters—either briefly or in detail. I would be genuinely grateful.
The argument I am presenting for my claim that the universe is contingent in time (i.e., it had a beginning) is based on observation.
1. The universe is in a constant state of change.
Everything in the universe is subject to change, and there is no rational or scientific objection to this observation. Every change involves a transition from one state to another, and such a transition cannot occur without time. Therefore, every genuine change presupposes temporal succession.
A simple example illustrates this. Suppose a person is angry at one moment and later becomes happy because of a different circumstance. The person’s condition has changed. Anger belonged to an earlier state, while happiness belongs to a later state. This demonstrates that a new state has come into existence, and the concepts of “before” and “after” necessarily imply the existence of time.
Science provides many examples of this relationship between change and temporal succession:
Radioactive decay: A radioactive atom gradually decays into another element. For example, uranium eventually decays into lead. This process occurs over time and clearly involves a “before” and an “after.”
Phase transitions: Ice absorbs heat and becomes liquid water. It was previously in a solid state and later exists in a liquid state.
Stellar evolution: Stars form from clouds of gas, enter the main sequence, and later evolve into red giants or other stages. These are successive stages that occur through time.
Mitosis: A single cell divides into two cells through a process that unfolds over time.
Wherever change exists, temporal succession also exists. Scientific observation shows that the universe is constantly changing. Every change indicates that one state has ended and another has begun.
If the universe is genuinely changing, then it must have had previous states. However, I argue that the past cannot be actually infinite. If the past were infinite, the present moment could never have been reached. The fact that we exist in the present suggests that the temporal past is finite and therefore had a beginning.
For this reason, since the universe is continually changing, and every real change requires temporal succession, I conclude that the universe is not eternal but had a beginning.
2. Concerning worship
From the atheist perspective, acts of worship performed by believers have no objective supernatural benefit or consequence because, according to atheism, God does not exist. Although some atheists acknowledge that religious practices may provide psychological or social benefits, they generally regard worship itself as unnecessary from an objective standpoint.
However, if a Creator truly exists and has imposed obligations and responsibilities upon humanity, then failing to fulfill those obligations would be a serious error. In that case, atheism would not merely be an intellectual mistake; it would also mean failing to fulfill one’s duties toward the Creator.
As far as I understand, these arguments support the conclusion that the universe had a beginning.
Some members have responded by saying that we can only observe the universe as it exists now and have no direct observation of its past. 
My response is that once we accept the reality of the present universe through observation, we also accept that it has undergone previous states. The present state necessarily implies a history of earlier states through which it arrived at its current condition.
Others have pointed out that we do not possess complete knowledge of the entire universe. I agree with that observation. 
However, another question naturally arises. We do know many things about the universe, and indeed a great deal of it. If my argument is accepted—that the universe is subject to change and therefore had a beginning—then the same principle should apply to those parts of the universe that we have not yet observed, because they are still part of the same universe, not something existing outside of it.