It is customary to see this as a reproof to Mary and the brothers. Well, it may be, but you don't have to read it like that.
Maybe you used to come to the house of God: Sunday worship, Monday prayer meeting, Wednesday Bible study. These are difficult things. Life is very highly pressured. Family life can be complex; all sorts of things have to be done. Not everybody can always come to everything they would like to come to, so we don't mean to hurt anybody, but maybe in your case you could come, but you don’t. You used to. Somebody says to you, ‘Why don't you come back to the Bible Study? You need it’, and you harden your heart, and you say, ‘No. I’ve got out of the habit. I don't want to do that.’ Here is the great sign of the true convert: ‘Whosoever shall do the will of God.’ If I can, and if it is the will of God, I will. I am touched; I am convicted; that is my life. That is the greatest sign of conversion: that you've really been changed, that you want to do the will of God. Maybe you are for the moment in this unsatisfactory state, and yet you are truly converted. What a shame, if you’ve slipped so that you resemble the person who isn't truly converted! It speaks to us all. But it is intended for comfort. If you do the will of God, you are truly converted, and Christ is as close to you as a brother or a sister, and he will be as patient with you as you would be to an ageing mother.