During our trip to Rome last winter, my family was able to walk through the holy doors at every major basilica in Rome, as well as Assisi and Pompeii.
In the beauty of all of those magnificent churches, we steeped in the early Church - the tradition and the history. In the enormous grandeur of these holy places, we were repeatedly reminded of the role of God's mercy (misericordia) in our faith. It's great to believe in God, but so humbling to know His mercy. "But God, who is rich in mercy, because of the great love he had for us, even when we were dead in our transgressions, brought us to life with Christ." Ephesians 2: 3-5. We don't deserve the love of God through Christ, it is a gift.
So does the closing of the mercy doors mean God's mercy ends? Of course not! "My mercy is established forever; my faithfulness will stand as long as the heavens." Psalm 89: 3-4. It is always there, in every age. As Pope Francis said today in his homily of the Solemnity of Jesus Christ, King of the Universe:
So many pilgrims have crossed the threshold of the Holy Doors, and far away from the clamour of the daily news they have tasted the great goodness of the Lord. We give thanks for this, as we recall how we have received mercy in order to be merciful, in order that we too may become instruments of mercy. Let us go forward on this road together.