Here is just a small sampling of the many verses in the Bible about unity.
Eph 4:1,3 Therefore I, a prisoner for serving the Lord, beg you to lead a life worthy of your calling, for you have been called by God.. 3 Make every effort to keep yourselves united in the Spirit, binding yourselves together with peace.
Rom 14:19 So then, pursue the things that make for peace and the building up of one another.
Col 3:14 Beyond all these things put on love, which is the perfect bond of unity.
Eph 2: 14 For He Himself is our peace, who made both groups into one and broke down the barrier of the dividing wall.
Psalm 133:1 Behold how good and pleasant it is when brothers dwell together in unity!
New American Standard Version