If time had a beginning, what is the implication for religion?
Time having a beginning poses absolutely no problem for religion as it is entirely consistent. It is well recognized that time is itself a creation that is part and parcel with the universe and that God, ie the cause, exists outside of time and physical space. In short, your circular logic is in error as both science and religion agree on this matter, even if the scale of matter seems grossly different. What religion can do that science, to date, cannot is explain what existed at time index = 0. For religion, it’s God….for science it’s ‘undefined’ due to a ‘divide by 0’ error. That time is a creation and had a beginning is therefore much more of a problem for science.