Jesus has just finished the parable of the sower, four kinds of hearing and only one that finally bears fruit, and this short saying about a lamp reads as its natural continuation. 16"No one after lighting a lamp covers it with a jar or puts it under a bed, but puts it on a stand, so that those who enter may see the light." A lamp exists to be seen. The word Jesus has been sowing works the same way. It is meant to be received openly enough that it eventually shows in a life and is not smothered when it starts to catch.
18"Take care then how you hear," Jesus says, and the instruction gathers up everything the sower parable taught. Hearing compounds in this Gospel. 18"to the one who has, more will be given, and from the one who has not, even what he thinks that he has will be taken away." A person who receives the word finds it growing, and it makes more room to receive still more. A person who only seems to have received it, like the rocky or thorny ground of the parable, discovers that even the little they appeared to hold was less secure than it looked.
Then, almost without warning, the scene turns painfully ordinary. 19"his mother and his brothers came to him, but they could not reach him." Mary, who once treasured every strange thing about this son's birth, is standing outside a packed house, unable to get near him. Someone passes the word along. 20"Your mother and your brothers are standing outside, desiring to see you." It would have been the simplest thing for Jesus to stop everything and go to them, and no one in the room would have thought less of him.
Instead he answers with a sentence that redraws the boundaries of family. 21"My mother and my brothers are those who hear the word of God and do it." Mary belongs in this sentence. She is the woman who said yes to the angel before any of this began, and who has treasured these events in her heart since the first chapter of the Gospel. If anyone has already shown what it means to hear the word of God and do it, it is she. He names the qualification for belonging to him, and it includes his own mother, and it opens the same door to everyone in that room who has never shared a drop of blood with him.
This is where the lamp saying and the sower have been heading. Hearing the word is only the first half of what this Gospel keeps asking for. Doing it, letting the word reach the visible surface of a life the way a lamp reaches the corners of a room, is what marks out who belongs to his family. Blood opens no door here that obedience does not also open, and closes none that obedience does not also close.
Consider which family you have been trying to belong to by listening. You can hear a sermon every week and still be standing outside the house. The invitation of this passage is to step in, by doing the small next thing the word has already told you.
Prayer
Father, thank you for a family whose membership was never limited by blood and is open to anyone willing to hear your word and do it. Teach us to take care how we hear, so that what you have given us stands on a lamp stand and stays out from under the bed. Make us true brothers and sisters of your Son by hearing his word and doing it today. In Jesus' name, amen.