"They shall find in my heart an assured refuge during life and especially at the hour of death."
Where do you run for shelter? Where can danger not touch you?
In Old Testament times, cities of refuge were ordered by God; places where people guilty of accidental crimes or sin could not be touched, for example, by the angry owners of an animal unintentionally killed.
Just as a bird seeks an opening in a cliff when the weather is bad, the Heart of Jesus was pierced with a lance, creating an opening, where we can find spiritual refuge. Our Lord's Heart was stabbed, pierced, broken open. Jesus gives His all, to the last drop. All is open, nothing is kept closed.
What pain do we have that He cannot identify with? What enemy do we face that He hasn't already faced?
We need refuge from three things. First, from ourselves. We are our own worst enemies. We doubt, our faith falters, we shift like sand. We ought never to trust in ourselves, as we prove unreliable time and time again. But in His Heart we find a compassionate teacher of constancy and reliability. Thomas doubted, and was invited by Jesus to find his faith by putting his fingers in the wounds, the openings in the flesh, the proof of Christ's love for us. What flesh was more torn apart and opened that His pierced Heart?
We need refuge from our worldly enemies; those who seek to harm us, in many ways. Did not Christ have His enemies? Did He not defeat them? To His heart, then, let us flee.
We need refuge from the devil, our enemy. The devil points to us and says, "Oh sinner! How often you have foresaken God and obeyed me instead! You are mine!" But we run to the Sacred Heart, full of mercy, and say, "I am a sinner, but a repentant one! His Heart which suffered for love of me is my refuge."
This we find not just in life, but especially at the hour of death, when we will face strong temptations to despair of God's mercy. We will be crossing over to a world beyond our control; where we will be at the mercy of God's terrible judgment. But His Heart bled for sinners. In this we can find reguge as we go to meet our Maker.