The Messenger of Allah (sal Allahu alaihi wa sallam) said: “Then I will come back to my Lord and praise Him in a similar manner. Then I will fall down prostrating before our Lord, and He will say, ‘O Muhammad, raise your head. Speak and you will be heard, ask and it will be given to you, intercede and your intercession will be accepted.’ I will say, ‘O Lord, my Ummah, my Ummah.’ He will say, ‘Go, and whoever has in his heart faith equal to a grain of mustard seed, bring him forth from the Fire.’ So I will go and do that.” [Saheeh Bukhaari]

Smaller than a grain of wheat or barley is a grain of mustard seed. But how much faith is “faith equal to a grain of mustard seed?” Consider the words of the Prophet (sal Allahu alaihi wa sallam) on this:

“Never before me had a Prophet been sent by Allah to his nation who had not among his people disciples and companions who followed his ways and obeyed his command. Then there came after them their successors who said whatever they did not practice, and practiced whatever they were not commanded to do. He who strove against them with his hand was a believer; he who strove against them with his tongue was a believer; and he who strove against them with his heart was a believer; and beyond that there is no faith, not even as minute as a mustard seed.” [Muslim]

So the least amount of faith (faith as small as a grain of mustard seed) requires that we at least hate in our hearts the practices that are against Islam. Less than this there is no faith! 

How do you feel when you see non-Mahram men and women socializing together? What is the condition of your heart when Muslims live in houses, drive cars or go to college on interest (Riba) bearing loans? Examine your feelings when you see a pretty woman not covered as Allah (subhana wa ta’ala) advised her to cover, or a man staring at women on T.V. How do you feel when Muslims turn away from the problems of Muslims? Do you find sadness, disgust and abhorrence in your heart when Allah’s commands are violated or not?