Nevertheless we made our prayer unto our God, and set a watch against them day and night, because of them (Nehemiah 4:9).
Prayer is a powerful weapon, but the wall-builders in Jerusalem also were careful to set a watch against their enemies with their swords, their spears, and their bows (Nehemiah 4:13). They were ready to fight if necessary, but at the same time they were confident that our God shall fight for us (Nehemiah 4:20).
This is a sound Biblical principle. God expects us to make appropriate use of whatever physical means are available for a needed ministry, rather than to rely simply on prayer and divine miracle. The Lord rebuked those who came asking Him to perform a miracle merely to test Him or to see something curious. Except ye see signs and wonders, ye will not believe (John 4:48). Neither does He condone prayer in lieu of work, for faith, if it hath not works, is dead, being alone (James 2:17). The same holds for prayer in lieu of obedience. As Joshua was praying for deliverance from the enemy, the LORD said unto Joshua, Get thee up; wherefore liest thou thus upon thy face? Israel hath sinned, and they have also transgressed my covenant which I commanded them (Joshua 7:10,11).
But as prayer without working is dead, so watching and working without prayer are futile. Ye lust, and have not: ye kill, and desire to have, and cannot obtain: ye fight and war, yet ye have not, because ye ask not (James 4:2). Except the LORD build the house, they labor in vain that build it: except the LORD keep the city, the watchman waketh but in vain (Psalm 127:1).
The Biblical principle is not only to watch or only to pray. Both are essential. Watch and pray, said Jesus, that ye enter not into temptation (Matthew 26:41). HMM