The text says "cleanses," not "shall cleanse." Many hope for forgiveness as a final wish at death. How much better it is to be cleansed now than to rely on the mere chance of forgiveness at life's end. Some think forgiveness is only reachable after years of faith.
Forgiveness is for today. It's a gift for this moment. The instant someone trusts Jesus, they are fully forgiven. The present tense of "cleanses" in the text shows it's ongoing. It cleansed yesterday, it's cleansing today, and it will cleanse tomorrow. This remains true for you, Christian, until your life's journey ends. Every moment, you can come to this fountain, for it cleanses continually.
Also notice the thoroughness of this cleansing. "The blood of Jesus Christ his Son cleanses us from all sin," not just from sin, but "from all sin." I can't fully express the sweetness of this truth, but I pray the Holy Spirit helps you grasp it. Our sins against God are many, yet the same redemption covers them all. Jesus' blood is sufficient for Peter's denials and John's failings alike.
Our sins are completely removed, gone forever. What a wonderful truth to ponder as we drift to sleep: "Sins against a holy God, sins against His righteous laws, sins against His love and blood, sins immense as the sea. From them all, He cleanses me."
Closing Prayer
Lord, as this day ends, help us to trust You completely, even when the way forward is unclear. Through Christ our Lord, Amen.