u ni ty /ˈ'yunɪ?ti/ [yoo-ni-tee]
–noun, plural -ties. 1.the state of being one; oneness.
2.a whole or totality as combining all its parts into one.
3.the state or fact of being united or combined into one, as of the parts of a whole; unification.
4.absence of diversity; unvaried or uniform character.
5.oneness of mind, feeling, etc., as among a number of persons; concord, harmony, or agreement.
6.Mathematics. a.the number one; a quantity regarded as one.b.identity (def. 9).
7.(in literature and art) a relation of all the parts or elements of a work constituting a harmonious whole and producing a single general effect.
8.one of the three principles of dramatic structure (the three unities) derived from Aristotelian aesthetics and formalized in the neoclassic canon in which a play is required to represent action as taking place in one day (unity of time), as occurring within one place (unity of place), and as having a single plot with a beginning, middle, and end (unity of action).

2 Chronicles 30:12 (New Living Translation)
12 At the same time, God’s hand was on the people in the land of Judah, giving them all one heart to obey the orders of the king and his officials, who were following the word of the Lord.
2 Chronicles 30:12 (New International Version)
12 Also in Judah the hand of God was on the people to give them unity of mind to carry out what the king and his officials had ordered, following the word of the LORD.

They wouldn’t have been able to carry out God’s plan without unity.

Psalm 133 (New King James Version)
1 Behold, how good and how pleasant it is For brethren to dwell together in unity! 2 It is like the precious oil upon the head,Running down on the beard, The beard of Aaron, Running down on the edge of his garments.3 It is like the dew of Hermon,Descending upon the mountains of Zion; For there the LORD commanded the blessing— Life forevermore.

Psalm 133 (The Message)
1-3 How wonderful, how beautiful, when brothers and sisters get along! It's like costly anointing oil flowing down head and beard, Flowing down Aaron's beard, flowing down the collar of his priestly robes. It's like the dew on Mount Hermon flowing down the slopes of Zion. Yes, that's where God commands the blessing, ordains eternal life.
Psalm 133 (New International Version)
1 How good and pleasant it is when brothers live together in unity!
2 It is like precious oil poured on the head, running down on the beard, running down on Aaron's beard, down upon the collar of his robes.
3 It is as if the dew of Hermon were falling on Mount Zion. For there the LORD bestows his blessing, even life forevermore.

Psalm 133 (Amplified Bible)
1
BEHOLD, HOW good and how pleasant it is for brethren to dwell together in unity!
2It is like the precious ointment poured on the head, that ran down on the beard, even the beard of Aaron [the first high priest], that came down upon the collar and skirts of his garments [consecrating the whole body].
3It is like the dew of [lofty] Mount Hermon and the dew that comes on the hills of Zion; for there the Lord has commanded the blessing, even life forevermore [upon the high and the lowly].

Think of living in a household with family. If all of you are at odd ends with eachother... how easy is living in one space with one another? How much stress and emotional complexity will there be? How are you able to keep the household running smoothly? So many fights would break out if there wasn’t unity. Without unity the house would become chaotic, and no doubt we’ll have a breakdown and do something unimaginable or we’ll nee some professional help :P
When your united with your family, there will be strength. You’ll love each other and help them with their weaknesses and hardtimes. It’s so much easier if we’d stop being selfish, mean spirited, judgmental, and hatefullness. Also God commanded it :P not an option if your following His word : )

John 17:20-26 (New International Version)
20"My prayer is not for them alone. I pray also for those who will believe in me through their message, 21that all of them may be one, Father, just as you are in me and I am in you. May they also be in us so that the world may believe that you have sent me. 22I have given them the glory that you gave me, that they may be one as we are one: 23 I in them and you in me. May they be brought to complete unity to let the world know that you sent me and have loved them even as you have loved me. 24"Father, I want those you have given me to be with me where I am, and to see my glory, the glory you have given me because you loved me before the creation of the world. 25"Righteous Father, though the world does not know you, I know you, and they know that you have sent me. 26I have made you known to them, and will continue to make you known in order that the love you have for me may be in them and that I myself may be in them."

John 17:20-26 (The Message)
20-23I'm praying not only for them But also for those who will believe in me Because of them and their witness about me. The goal is for all of them to become one heart and mind— Just as you, Father, are in me and I in you, So they might be one heart and mind with us. Then the world might believe that you, in fact, sent me. The same glory you gave me, I gave them, So they'll be as unified and together as we are— I in them and you in me. Then they'll be mature in this oneness, And give the godless world evidence That you've sent me and loved them In the same way you've loved me.
24-26Father, I want those you gave me To be with me, right where I am, So they can see my glory, the splendor you gave me, Having loved me Long before there ever was a world. Righteous Father, the world has never known you, But I have known you, and these disciples know That you sent me on this mission. I have made your very being known to them— Who you are and what you do— And continue to make it known, So that your love for me Might be in them Exactly as I am in them.

So I pointed out why unity was important, and that God had commanded unity, but... we also have to put our differences aside, and not care about the differences that are in between us. I’m sure God doesn’t agree with everything we think we believe is right. After all we are all human. Just because someone believes something is different from someone else, doesn’t mean we leave them high and dry. I know it’s hard, I have sat there and thought ‘Is this person freaking crazy, or what?’. But I’m working on putting those differences apart and focusing on love and the plan God is having us carry us out. We all have the same command either way. (I.e. something we have in common)

Romans 15:5-8 (New International Version)
5May the God who gives endurance and encouragement give you a spirit of unity among yourselves as you follow Christ Jesus, 6so that with one heart and mouth you may glorify the God and Father of our Lord Jesus Christ.
7Accept one another, then, just as Christ accepted you, in order to bring praise to God. 8For I tell you that Christ has become a servant of the Jews
on behalf of God's truth, to confirm the promises made to the patriarchs


Romans 15:5-8 (The Message)
3-6That's exactly what Jesus did. He didn't make it easy for himself by avoiding people's troubles, but waded right in and helped out. "I took on the troubles of the troubled," is the way Scripture puts it. Even if it was written in Scripture long ago, you can be sure it's written for us. God wants the combination of his steady, constant calling and warm, personal counsel in Scripture to come to characterize us, keeping us alert for whatever he will do next. May our dependably steady and warmly personal God develop maturity in you so that you get along with each other as well as Jesus gets along with us all. Then we'll be a choir—not our voices only, but our very lives singing in harmony in a stunning anthem to the God and Father of our Master Jesus!

7-13So reach out and welcome one another to God's glory. Jesus did it; now you do it! Jesus, staying true to God's purposes, reached out in a special way to the Jewish insiders so that the old ancestral promises would come true for them. As a result, the non-Jewish outsiders have been able to experience mercy and to show appreciation to God. Just think of all the Scriptures that will come true in what we do! For instance: Then I'll join outsiders in a hymn-sing; I'll sing to your name!And this one: Outsiders and insiders, rejoice together!And again: People of all nations, celebrate God! All colors and races, give hearty praise!And Isaiah's word: There's the root of our ancestor Jesse, breaking through the earth and growing tree tall, Tall enough for everyone everywhere to see and take hope!Oh! May the God of green hope fill you up with joy, fill you up with peace, so that your believing lives, filled with the life-giving energy of the Holy Spirit, will brim over with hope!


Romans 12:4-6 (New International Version)
4Just as each of us has one body with many members, and these members do not all have the same function, 5so in Christ we who are many form one body, and each member belongs to all the others. 6We have different gifts, according to the grace given us. If a man's gift is prophesying, let him use it in proportion to his[a]faith.

Because we are all different, We think different. God made us this way for a reason. Our though processes are different, we perceive things differently.
I’m not condemning anyone, I’m speaking to myself on this one also. I started writing this thinking I’ve got it down to be honest. But as I started writing I started realizing who I leave out of the loop. They’re equal, no matter what they believe. We all sin. Even though Emery’s song (Listening to Freddie Mercury) is not about unity, it has the right idea.
We snub people all the time because of the certain denominations they are, but it’s not about that. It’s about uniting to fight the spiritual battle before us, this isn’t a divide and conquer. Now really think about it, drink it in, meditate on it. You might be surprised.