The prophet, Isaiah, saw a vision of God in which he fell to the ground because of his unworthiness. Isaiah was royalty! Who was he to fall at the Feet of the Lord with feelings of unworthiness? He could have said, "Well, I, too, am a king! Here is my dominion!" Instead, Isaiah cast aside any thoughts of grandeur and surrendered to the Glory of God that filled the whole earth.
As a result of this humility, an angel came with a burning ember from the altar of the Lord and touched it to Isaiah's lips. This flaming bit of sacred wood burnt away Isaiah's sin and prepared him to become a sacred servant of God.
Here's the cool connection - the priest explained this as a precursor to the Mass. We come before God and recognize our unworthiness. In His Mercy, God sends us the burning ember of the Cross to purge us of our sin. Christ's Sacrifice is our salvation, and just as the ember was dispatched to Isaiah from God's altar, so too, does Christ's Sacrifice come to us through God's altar. Christ's Body, the Perfect Holocaust, passes through our lips to cleanse us body and soul that we may be transformed, going forth to become true servants of God.
In order for this transformation to take place, however, we need Isaiah's humility. We need to admit our faults to God just as Isaiah cried out his unworthiness. Isaiah cried out to the angels. We were given our priests in the Sacrament of Reconciliation. We would do well to take part in this Sacrament often as a way to show humility to God and prepare to receive Him in the Eucharist.
So that was the cool connection for me. I never thought of the ember being touched to Isaiah's lips as anything more than a burning piece of charcoal or something that was a symbol of his purification. Now I realize it was another example of God's foreshadowing the even greater purification that would take place for all His children through Christ.
I admit... I love connections like that!