You don’t get the staggering point of that verse.....Jesus would deny his own mother if she did not do the will of the Father! That was the importance Christ spiritually placed upon his own earthly family. If you and I do the will of the Father then we are considered like his very own Father, mother sister and brother!
Now Mary did the will of the Father so I am not negating Mary. Jesus’ own attitude though stands in stark contrast to the hyper importance Catholics have placed upon Mary in the heavenly scheme of things! Note that the verse takes the time to state that Christ when told of Mary’s presence.. Christ “stretched forth his hand” toward the disciples as he spoke “those who do the will of the Father are my mother, sister, and brother”. A lot of people overlook that aspect of that passage...of Christ pointing at the disciples as he spoke of our heavenly duties. That the writer of Matthew took the time to mention that simple gesture tells me that the observer took what Jesus said very much to heart. Mary mothered Jesus, the angel said she would bear “a son”, but Christ said only those who did the will of the Father would be considered his “mother, sister, and brother”!
I do understand the full impact of what Jesus said. As His mother, Mary was sometimes more concerned about Jesus as her son than she was about Jesus as the Son of God. He reminded her of this when He was 12, and again at the wedding feast in Cana. And in this passage, Jesus was letting everyone know that it is always about the will of the Father.