Direct biblical statement
John 19:25–27
At the foot of the Cross
25 Now there stood by the cross of Jesus, his mother and his mother's sister, Mary of Cleophas, and Mary Magdalen.
26 When Jesus therefore had seen his mother and the disciple standing whom he loved, he saith to his mother: Woman, behold thy son.
27 After that, he saith to the disciple: Behold thy mother. And from that hour, the disciple took her to his own.
Douay–Rheims · Challoner revision · John 19:25–27
Why this matters
Mary stands beside the Cross. Jesus entrusts her and the beloved disciple to one another, and the disciple receives her. Catholic tradition also reads spiritual motherhood in this act; that extension is theological interpretation beyond the immediate provision of care.