In Ephesians 6:18, Paul talks about the spiritual armour, "Praying always with all prayer and supplication in the Spirit..."
The spear and lances used by the Roman army varied greatly in size, shape and length. These weapons were devised to be used to attack an enemy from a distance. They were thrown with great force and hurled to strike an enemy from afar. As they were thrown at different distances, they came in all sizes and shapes. The particular lance chosen by a soldier depended on how it was to be used.
By revelation, Paul begins to compare these various lances to the various kinds of prayer God has made available to us. This is why he said, "Praying always, with all prayer and supplication..." When a believer uses prayer, it becomes a lance that can be thrown forth into the spirit realm against the works of the adversary. By forcibly hurling this divine instrument of prayer into the face of the enemy, a believer can exert great spiritual power, literally attacking the devil from a distance in order to stop major obstacles from developing up close in his personal life.
Don't wrongly assume that all prayer is of the same kind. Just as Roman soldiers used all kinds of lances in battle, Paul lets us know that there are many forms of prayer. For example, there is a prayer of faith, the prayer of agreement, the prayer of intercession, the prayer of supplication, the prayer of petitition, the prayer of consecration, the prayer of thanksgiving, united prayer and so forth.
Paul instructs us to use every form of prayer that has been available to us as it is needed. No one kind of prayer is better than the others; each serves a different and necessary purpose in the life of faith.
Never forget that prayer is a vital piece of your spiritual weaponry. If you neglect this strategic piece of weaponry, you will find that the enemy keeps attacking you from up close. But as you learn to pray with authority, you will develop the ability to strike the enemy from a distance and therefore maintain a victorious position in life.
God has placed the lance of prayer at your disposal, so you can be assured of absolute and total victory.
