From The Mirrors - Exodus 38:8

Exodus 38:8 ESV
He made the basin of bronze and its stand of bronze, from the mirrors of the ministering women who ministered in the entrance of the tent of meeting.

Why would it be important to add that the basin was made up from the mirrors of the ministering women?

The basin was to be used for washing, to make one clean as they approached the tent of meeting. It was placed between the alter and the tent, and filled with water.

It was referred to as the sea.
It reminds me of the sea before the Father's throne, which might be symbolic of the many waters, of the many peoples through time and place from whom God will gather a people who will listen, obey, and seek the life of God. It is this journey through creation that leads us to the presence of God.

Jesus would take a basin and wash the feet of the disciples, saying that washing one's hands and feet was all that was needed for someone who has bathed. We are bound to be soiled if we walk on this earth and touch it along the way.

Perhaps the mirrors remind us that we must look at ourselves intently before we can wash ourselves clean in the blood of the Lamb. We must look at our own reflection as we look into the word of God. When we do that we can begin to see the person passing and the new creation. May we always have that new creation before us.

Exodus 40:30-31
He set the basin between the tent of meeting and the altar, and put water in it for washing, with which Moses and Aaron and his sons washed their hands and their feet.

1 Kings 7:23
Then he made the sea of cast metal. It was round, ten cubits from brim to brim, and five cubits high, and a line of thirty cubits measured its circumference.

Psalms 26:6-7
I wash my hands in innocence
and go around your altar, O Lord,
proclaiming thanksgiving aloud,
and telling all your wondrous deeds.

Zechariah 13:1
“On that day there shall be a fountain opened for the house of David and the inhabitants of Jerusalem, to cleanse them from sin and uncleanness.

John 13:5
Then he poured water into a basin and began to wash the disciples 'feet and to wipe them with the towel that was wrapped around him.

John 13:10-11
Jesus said to him, “The one who has bathed does not need to wash, except for his feet, but is completely clean. And you are clean, but not every one of you.” For he knew who was to betray him; that was why he said, “Not all of you are clean.”

Titus 3:5-7
he saved us, not because of works done by us in righteousness, but according to his own mercy, by the washing of regeneration and renewal of the Holy Spirit, whom he poured out on us richly through Jesus Christ our Savior, so that being justified by his grace we might become heirs according to the hope of eternal life.