Today's first reading at Mass, from the prophet Isaiah, contains a phrase that bears much thinking about. What does it mean to be a "clean vessel"? For a long time I used to think in terms of Jewish ritual purity, then in terms of moral uprightness, freedom from sin. Clearly, all those ideas are legitimate and worth pondering, but doing the washing-up this morning made me think again, and the thought is so obvious that I hesitate to put it before you.

A clean vessel is one that has been washed, of course, but also one that is empty, waiting to receive that which it is meant to contain. You don't call a full cup "clean" (although one trusts it was clean when you filled it) you only call an empty cup "clean". Isn't that how we all go to prayer, empty, waiting to be filled?

It's an aspect of the openness we talk about in this week's prayer podcast: being open to others, open to the Holy Spirit. It requires effort on our part but it's an effort worth making: to be filled with the utter fullness of God.