Unity is based on the Book and the Sunnah and not bidah. We do not look for a common enemy and unite against him… because as soon as we overcome him, we will start to fight amongst ourselves.
Shaikh Uthaymeen [rahimahullaah] said: If a person says: What will make a man love his wife and vice versa? We say: Allaah has clarified this in His statement:
وَعَاشِرُوهُنَّ بِالْمَعْرُوفِ
And live with them honourably. [Soorah An-Nisaa’ Aayah 19]
If every person lives with his wife honourably and vice versa, then love, a strong bond and a happy married life will be established.
And among His Signs is this, that He created for you wives from among yourselves, that you may find repose in them, and He has put between you affection and mercy. Verily, in that are indeed signs for a people who reflect.” [Soorah Ar-Rum: Ayah: 21]
Imaam as-Saa’di [rahimahullaah]: ”In most cases you will not find love in anyone similar to the love and mercy between a husband and wife.”
And verily, this is my Straight Path, so follow it, and follow not [other] paths, for they will separate you away from His Path. This He has ordained for you that you may become Al-Muttaqun [the pious] [6:153]
Abu Nu’aym [rahimahullaah] reported with his chain of transmission from Mujaahid [rahimahullaah] regarding the statement of Allaah: [وَلَا تَتَّبِعُواْ ٱلسُّبُلَ فَتَفَرَّقَ بِكُمۡ عَن سَبِيلِهِ – And follow not [other] paths, for they will separate you away from His Path], that it means: [Do not follow] Bidah [i.e. innovations in religion] and Shubuhaat [i.e. affairs that are made to resemble truth but are falsehood in reality].
[Source: Al-Hilya 3/293. Abridged and slightly paraphrased]
On the Authority of Al-Hussain ibn Al-Hasan Al-Maroozee who said: I heard ibnul Mubaarak say:
“The people of the dunya exited the dunya before tasting the sweetest of that which is in it. It was said to him, and what is the sweetest of that which is in it?
He said: Ma’rifatu Allah – azza wa jal – (knowledge and awareness of Allah).”
“Whoever wants to know if he loves Allah and His Messenger then let him look! If he loves the Quraan (reciting it, acting upon it), then indeed he loves Allah and His Messenger (sallallaahu alaihi wa sallam).”