Question: What is the ruling of the learned Ulama about what is Imaan-e-Kaamil (Completely strong Imaan) and how can one make ones Imaan Kaamil?

The Answer: To accept every word of the Prophet Sall Allaho Alaihi Wa Sallam as true and correct and to accept the righteousness of the Prophet Sall Allaho Alaihi Wa Sallam with sincerity is Imaan. One who fulfills this is called a Muslim, for as long as any of his words or actions or condition does not show rejection to Allah and His Rasool Sall Allaho Alaihi Wa Sallam or he does not falsify what they mention or he does not make blasphemy. Now, one who shows his connection to Allah and His Rasool Sall Allaho Alaihi Wa Sallam more than to anyone else and one who loves those who love Allah and His Rasool Sall Allaho Alaihi Wa Sallam, even if they are his personal enemies and he hates and shuns those who speak against Allah and His Rasool Sall Allaho Alaihi Wa Sallam even if they are his close and loved ones and if he gives what ever he gives for the sake of Allah and if he holds back anything, he does so for Allah, then he has Kaamil Imaan and this is as mentioned by the Holy Prophet Sall Allaho Alaihi Wa Sallam who said, “One who loves for Allah and hates for Allah and gives for the sake of Allah and holds back for the sake of Allah has complete Imaan.”

كتبه عبده المذنب احمد رضا عفى عنه

بمحمّد 

From al-Malfūdh Sharif, pg 86:

The first and foremost factor of Imān is respect for the Rasūl şallAllāhu álayhi wa sallam. Salāh or any form of ‘ibādah is useless without reverence for the Beloved Rasūl şallAllāhu álayhi wa sallam. There are many ‘Abd-Allah’s [servants of Allah Almighty] in this world, but the true and sincere ‘Abd-Allah is he, who is ‘Abde-Mustafa [servant of the Beloved Prophet şallAllāhu álayhi wa sallam]. If it is not so, then he is surely an ‘Abde-Shaytan [servant of the cursed devil]. May the Merciful Allah Almighty save us all from this curse! [Ameen!]