All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
Believers vary greatly in faith and no one has ever reached perfect faith, except the prophets, the most perfect amongst them being the Prophet Muhammad, sallallaahu ‘alayhi wa sallam.
Variations in faith occur according to a person's certainty in Allaah The Almighty, belief in Him, love for Him, seeking His favor, fearing Him, depending on Him, submitting to His orders, and being pleased with His Predestination and Decree, etc. Faith also varies according to a person's adherence to the good deeds that have been commanded by Allaah, and avoidance of prohibited bad deeds.
There are signs that can indicate the strength of a person's faith:
1- Giving priority to what Allaah and His Messenger, sallallaahu ‘alayhi wa sallam, love over what a person desires and loves.
2- Sacrificing oneself, money and all that is precious for the sake of Allaah.
3- Loving those whom Allaah and His Messenger, sallallaahu ‘alayhi wa sallam, loves and detesting those who hate Allaah and His messenger, sallallaahu ‘alayhi wa sallam, and do not believe in them.
4- Being pleased with Allaah's Predestination and Decree, and not being discontent or sorrowful when afflicted with a calamity.
5- Hasting to do good deeds and keeping away from sin and immorality.
6- Being assured and pleased when mentioning Allaah, as Allaah Says (what means):
· {Those who have believed and whose hearts are assured by the remembrance of Allaah. Unquestionably, by the remembrance of Allaah hearts are assured."}[Quran 13:28]
· {The believers are only those who, when Allaah is mentioned, their hearts become fearful, and when His verses are recited to them, it increases them in faith; and upon their Lord they rely* The ones who establish prayer, and from what We have provided them, they spend.* Those are the believers, truly. For them are degrees [of high position] with their Lord and forgiveness and noble provision.-}[Quran 8:2-4]
7- Having certainty in Allaah, and taking refuge with Him. Allaah Says (what means): {Surely the believers are only the ones who have believed in Allaah and His Messenger; thereafter they have not been suspicious, and have striven with their riches and their selves in the way of Allaah; those are they (who are) sincere.}[Quran 49:15]
8- Being happy when performing acts of obedience and feeling sorry when committing a sin. The Prophet, sallallaahu ‘alayhi wa sallam, said that whoever is pleased with doing good deeds and displeased and full of grief when committing sins is a true believer. [At-Tirmithi, Ahmad and Al-Haakim]
Allaah Knows best.