As Du’ât, we should aim for the highest level of being Muslims by having ihsan, which according to the Prophet (sallallâhu ‘alayhi wasallam) is “… to worship Allah as if you see Him, and if you cannot achieve this state of devotion then you must consider that He is looking at you.” (Bukhari 1/47, 6/300 and Muslim1) We should be Mu’hsinoon or Muttaqon (God conscious or God-fearing Muslims). This means that we have to remember and fear Allah (Subhanahu wa ta’ala) at all times. We have to be righteous and pious and restrain and guard ourselves from evil. We have to be strong in conveying the Truth and should not fear anyone but Allah (Subhanahu wa ta’ala). We should see to it that everything we think, we say, and we do is Islamic ¾ in complete submission to the Will of Allah (Subhanahu wa ta’ala). We should have Taqwa (fear of Allah), which is a virtuous conduct in the Sight of Allah (Subhanahu wa ta’ala):
Abu Hurairah (radhiallahu anhu) narrated that “Allah’s Messenger (sallallâhu ‘alayhi wasallam) was asked, “Who are the most honorable of the people?” The Prophet (sallallâhu ‘alayhi wasallam) said, “The most honorable of them in Allah’s Sight are those who keep their duty to Allah and fear Him…” (Bukhari 6/211)
Verily, Allah (Subhanahu wa ta’ala) is the Only One Who deserves our fear. We should fear Him Alone as He knows the secrets of our hearts and is well acquainted with all that we do (5:7-8). Allah (Subhanahu wa ta’ala) says:
“O you who believe! Fear Allah as He should be feared, and die not except in a state of Islam. And hold fast, all together, by the rope which Allah (stretches out for you), and be not divided among yourselves…” (3:102-103)
“It is only the Evil One that suggests to you the fear of his votaries: be not afraid of them but fear Me if you have faith.” (3:175)
“And call in remembrance the favor of Allah unto you, and His Covenant, which He ratified with you, when you said: “We hear and we obey”: and fear Allah, for Allah knows well the secrets of your hearts.” (5:7)
“To Him belongs whatever is in the heavens and on earth and to Him is duty due always: then will you fear other than Allah?” (16:52)
“Turn your back in repentance to Him and fear Him: establish regular prayers and be not among those who join gods with Allah.” (30:31)
“O you who believe! Fear Allah, and let every soul look to what (provision) he has sent forth for the morrow. Yea, fear Allah for Allah is well-acquainted with (all) that you do.” (59:18)
We should as much as possible inculcate in our minds and hearts the fear of Allah (Subhanahu wa ta’ala). Wherever we are, we have to fear Allah (Subhanahu wa ta’ala), do good deeds and deal with people nicely:
Abu Dharr (radhiallahu anhu) narrated that Allah’s Messenger (sallallâhu ‘alayhi wasallam) said to him, “Fear Allah wherever you are; if you follow an evil deed with a good one you will obliterate it; and deal with people with a good disposition.” (Tirmidhi 5083)
Ali Bin Abu Talib (radhiallahu anhu) narrated that the last words, which Allah’s Messenger(sallallâhu ‘alayhi wasallam) spoke were: “Prayer, prayer; fear Allah about those whom your right hands possess.” (Abu Dawud 5137)
The non-Muslims should also know that they should fear no one but Allah (Subhanahu wa ta’ala). Allah is Most Gracious, Most Merciful, but His Wrath is Most Severe for those who deny Him. They should fear Allah; for Allah (Subhanahu wa ta’ala) is strict in punishment (5:2). Allah the Almighty warns:
“O you who believe! Devour not usury doubled and multiplied; but fear Allah; that you may (really) prosper. Fear the Fire that is prepared for those who reject faith. And obey Allah and the Messenger, that you may obtain mercy.” (3:130-132)
And if you are in doubt as to what We have revealed from time to time to Our servant then produce a Surah like thereunto; and call your witnesses or helpers (if there are any) besides Allah if your (doubts) are true. But if you cannot and of a surety you cannot then fear the fire whose fuel is Men and Stones which is prepared for those who reject Faith. (2:23-24)
It is necessary that we should have fear of Allah (Subhanahu wa ta’ala) and, at the same time, must have hope in His Mercy and Rewards. We do Da’wah as best as we can, not only out of fear of Him that if we do not do it based on the Qur’an and the Sunnah, Allah (Subhanahu wa ta’ala) will not only reject our deeds but also will punish us. Moreover, we do it the way the Prophet (sallallâhu ‘alayhi wasallam) did it out of hope that by doing righteous deeds, for His Pleasure, He will reward us. We should make this very clear to both the non-practicing Muslims and the non-Muslims. They should have fear in Allah’s punishment and hope in His Rewards. They should be made to understand that fear of Allah (Subhanahu wa ta’ala) gives us hope for ultimate success. It is one of the keys to salvation. Both the Qur’an and the Ahâdîth tell us:
“On the other hand for those who fear their Rabb are gardens with rivers flowing beneath therein are they to dwell (for ever) a gift from the presence of Allah and that which is in the presence of Allah is the best (bliss) for the righteous.” (3:198)
“O you who believe! If you fear Allah, He will grant you a criterion (to judge between right and wrong) remove from you (all) evil (that may afflict) you and forgive you: for Allah is the Rabb of grace unbounded.” (8:29)
“As for those who fear their Rabb Unseen, for them is Forgiveness and a great Reward.” (67:12)
Abu Hurairah (radhiallahu anhu) narrated that Allah’s Messenger(sallallâhu ‘alayhi wasallam) said, “Do you know the things which most commonly bring people into Paradise? They are fear of Allah and good character. Do you know what most commonly bring people into Hell? They are the two hollow things: the mouth and the private parts.” (Tirmidhi 4832 and Ibn Majah)
Abu Said (radhiallahu anhu) narrated that the Prophet (sallallâhu ‘alayhi wasallam) mentioned a man from the previous generation or from the people proceeding your age whom Allah had given both wealth and children. The Prophet (sallallâhu ‘alayhi wasallam) said, “When the time of his death approached, he asked his children, ‘What type of father have I been to you?’ They replied: ‘You have been a good father.’ He said, ‘But he (i.e. your father) has not stored any good deeds with Allah (for the Hereafter): if he should face Allah, Allah will punish him. So listen, (O my children), when I die, burn my body till I become mere coal and then grind it into powder, and when there is a stormy wind, throw me (my ashes) in it.’ So he took a firm promise from his children (to follow his instructions). And by Allah they (his sons) did accordingly (fulfilled their promise). Then Allah said, ‘Be!’ and behold! That man was standing there! Allah then said, ‘O my slave! What made you do what you did?’ That man said, ‘Fear of You.’ So Allah forgave him.” (Bukhari 8/488)
Ref. http://www.wefound.org/texts/Allah_files/Fear&HopeinAllah.htm