"When Jesus saw his mother, and the disciple whom he loved standing near, he said to his mother, 'Woman, behold, your son!' Then he said to the disciple, 'Behold, your mother!' And from that hour the disciple took her to his own home" (John 19:26-27 RSV).
It is considered a 'given' that "the disciple whom he loved" was John, and a myriad of traditions and legends have grown over the years concerning this directive from the cross. On its surface it's pretty straightforward: Jesus is entrusting the care of his mother to his closest disciple. The aftermath of the crucifixion is, at this point, unpredictable. It could be that the authorities will also turn against the family and disciples of Jesus; Mary may need protection. One wonders where James, the brother of Jesus, stands in all this, but apparently Jesus feels that John would be more reliable.
Metaphysically, the crucifixion represents those challenging times in our own lives when the furthering of our spiritual consciousness is at painful odds with the demands and fears of our human lives. The answer is always to surrender to Spirit, moving through the resistance to the 'resurrection' into a new dimension of spiritual awareness and expression. And as difficult as it is for us, it can also be challenging to those who are part of the level of consciousness we are surrendering. It's important, I think, that Jesus recognized this and sought to ensure that his spiritual surrender did not leave his mother vulnerable and alone. It can be difficult, at these 'crucifixion moments,' to take our focus off our own pain and lovingly consider our affect on others. It is important that we do just that, so we know in surrendering that we leave nothing but love behind.