Loins girt about with Truth. In Biblical times to 'Gird up your Loins' would be to wrap the bottom of you cloak into your belt, and by doing so you would be more able to move about and perform the days labor. You really don't want your clothing to limit your movement in battle.
The Breastplate of Righteousness. The Breastplate covers your Heart and Lungs, as well as other vital organs. When the scriptures say that in the last days, "men's hearts shall fail them", (Luke 21:26) it is because they do not have their Breastplate protecting them. Your Righteousness, which is your diligent obedience to the Commandments of God, will protect you from having your heart fail you.
Feet Shod with Preparation of the Gospel. When the Hebrews were 'Preparing' to leave Egypt they were told to eat the Passover. This was done with their Shoes on their feet and their staff in hand, and you ate while standing. This is because even though they had not yet received permission to leave Egypt, they were planning on going somewhere.
Whenever I go home for anything my Mommy always gets frustrated with me because I never take my jacket off. This has several reasons behind it, but the first and foremost reason is because I like having my jacket on, even in the middle of the summer. Then there are the reasons that are actually logical, like my jacket is somewhat a safety object and i am more comfortable around people when I am wearing it. My jacket has all my stuff in the pockets, my keys, my iPod, my phone, and an assortment of other things for the day. My jacket is what prepares me to go do what I need to later, and I don't take it off just because I am going to sit down for a few minutes.
A Shield of Faith. You must have Faith in order to be equipped with your best defense, your Shield. This Faith is required because when you put your Shield up you cannot see your enemy. You cover your head and most of your upper body to block the opponents sword, but also block him from your eyes.
Much like when Luke Skywalker puts the BlastSHIELD down and cannot see the remote, but must follow the promptings within, or his instinct, to know what to do.
The Helmet of Salvation. The Helmet protects YOUR BRAIN. There are a few things we need to know in order to return and live with our Heavenly Father. First is that Jesus Christ is His only Begotten Son in the Flesh. Second is the Plan of Salvation. Once you have a Knowledge you must protect it and continue learning.
The Sword of the Spirit, which is the Word of God. The only offensive weapon you have in the Armor of God is the Sword of the Spirit. In combat your sword is your life, you need it in hand if you are to fight the foe.
If you do not have your sword and you go up to battle anyway, your only option is to try and block the blows of your enemy. Sure you have your other Armor, but how long can your Shield last when it is being beat upon repeatedly. How long do you think it would be before your breastplate either came loose, or perhaps had a small gap between the plates where the enemy's sword found a way through. How long before your legs grew tired and you trip over your own feet.
The answer, not very long at all.
Without the Spirit you begin to lose faith (Shield), it is harder to keep the commandments (Breastplate), and you become less prepared for the fight (Feet Shod). Once you lose these other pieces of Armor you are an easy target and then POOF, you die. When it comes to the Armor of God you die Spiritually, and Christ is the Light and Life of the world, therefore the only way back is through His Atonement.
So remember to always have your Armor, and be on Guard.
"And it came to pass that I said unto them
The Scriptures are the Word of God. Both the Bible and the Book of Mormon. God teaches only Truth, and therefore the Wicked take the Scriptures to be Hard.
Keep the Commandments, Read the Scriptures, and do whatever it takes to truly have the Spirit with you at all times, in all things, and in all places.
The Sword of the Spirit is the Spirit of Truth.
Truth will fight your battles for you, as long as you keep it close by, and in your Heart.