“Jesus Christ is the same yesterday and today and forever”. Therefore, there are no impossibilities of time and space for what Jesus Christ was He is, and what He is, He was.
This remission of all sins is not limited to past sins only, but to all sins—past, present, and future. If it were not so, then justification would have to be repeated over and over again, and the imputation of the righteousness of Christ would be lowered to the level of the animal sacrifices of the old covenant. Therefore it has to be offered over and over again for the continued presence of sin.