“Put on the full armour of God”. 

Eph 6:13 NIV 
Those who fight in wars need to be fully fit. Rigorous medical tests are carried out on new recruits to ensure that they are strong enough “to take it”. Paratroop regiments are formed from those who volunteer and are prepared to undergo more exacting physical training than ordinary soldiers. Some volunteer because they have a “macho” attitude and use the training as an opportunity to develop their physique. 
When Paul wrote to the Ephesian church he was in Rome. He was a prisoner but was allowed more privileges than we would expect today. He seems to have lived at home but was guarded by a Roman soldier in a form of house-arrest. As he wrote, then, he could see the guard. He looked carefully and saw the uniform and some pieces of the man’s equipment. He no doubt looked formidable – and the dress and equipment are all designed to make the man himself feel powerful and strong. There must be nothing soft or sloppy about the appearance of a soldier who is on guard. He must look strong, tough and ready for action so that nobody would want to attack whatever he was guarding. It seemed to Paul that the man in front of his eyes was a model for how a Christian believer needed to be – armed and ready to withstand an attack at any time. 
Don’t wait for the Devil to attack you before you prepare yourself. Get armed with plenty of prayer. Study and know as much of the Bible as you possibly can. Walk with God. Absorb the lessons taught in worship. And be on the watch for Satan. 

Lord, arm me with all the spiritual equipment I can get.