A Christian leader writes: ‘The Great Wall of China was erected in the third century BC as a defence against raids by nomadic peoples from the north. Throughout succeeding centuries, especially during the Ming Dynasty (1368-1644), the Great Wall was repaired and extended in length, finally stretching for forty-five-hundred miles.’ Centuries before it began, biblical cultures used walls to protect themselves, and to draw boundaries around themselves for the purposes of identifying the land which was theirs. To be effective, however, those walls had to be regularly maintained. The slightest breach could give the enemy a fateful advantage. There is a valuable lesson here. As a Christian, there is one wall in your defence system that has to be maintained and protected at all times – the wall of self-control. The Bible says, ‘Whoever has no rule over his own spirit is like a city broken down, without walls.’ Your failure to maintain self-control is like opening the city gates and issuing an invitation to the devil to attack you. J. Wilbur Chapman, one of history’s great preachers, formulated what he called ‘my rule for Christian living’. And it’s a rule you should endeavour to live by. He said, ‘The rule that governs my life is this: anything that dims my vision of Christ, or takes away my taste for Bible study, or cramps my prayer life, or makes Christian work difficult, is wrong for me, and I must, as a Christian, turn away from it.’ Question: have your boundary walls been breached or fallen into disrepair? If so, do something about it today.