We also have the help of the souls in purgatory and we help them. This is not some belief of the past. There are truly souls that are being put through the refiner’s fire (Mal 3:3). In fact, all people must go through purification. While we are here on earth, Jesus purifies us with truth and love. Purification might hurt, but can be good for us in the same way not getting what we want can be good for us. But how do we know there is a purgation in the afterlife?
First of all, we know nothing unclean can enter heaven (Rev 21:27). Heaven is a place of utter peace and joy. There are no sins or regrets in heaven. Everybody is at peace with each other. There will be no more fighting or enemies in heaven (Lk 15:7). Imagine if you misjudged a person and became enemies with them and they died. Years later you die and find them in heaven. Will there be tension? Probably. So then you would not be fit for heaven. But Jesus in His goodness and wisdom allows us to be purified so we can be with Him. These are the people described in Mt 5:25-26 where there will be a paying of the “last penny”. In hell, there will be no paying of the last penny. But the torment described is not heaven.
Second Maccabees chapter 12 talks about how certain soldiers who were holding onto their worship idols were found dead on the battlefield (v40). Judas Maccabeus lead the others in prayer and supplication to atone for the sins of those soldiers (v42-46). So we can help those who have died. Our prayers make a difference. Even in Mark chapter 2, the four men who lower the paralytic intercede for him and Jesus, “saw their faith [and] said to the paralytic, ‘child, your sins are forgiven.’” (v5). They didn’t even say anything, but their works was their faith that Jesus saw. They were common, every day, average Joe type of men. Your everyday type of prayer is just as effective. The souls in purgatory need your prayers and, in fact, benefit from them.
The souls in purgatory cannot pray for themselves. Like the story of the rich man and Lazarus, it is too late to change minds (Lk 16:22). Once we are judged, it is done. So we are the only ones who can pray for them. We can pray, offer Mass, or do good works, in honor of them. It is a way in which Jesus allows us to participate in His work. He is the true intercessor. He really does not need us to do it. We just learn more to love in the process. So, like the father who allows his child to build something for the home, so our Father invites us to build up our home in heaven.