Firaasah is a sense of visual acumen, perception and insight. Allah says, "Surely! In this are the signs for the mutawassimeen." [15:75]
And with the regard to the meaning of mutawassimeen, here is what some of the great interpreters of the Qur'an said about it: Mujahid said it is "those who have visual acuity". Ibn Abbas said that it means "those who watch closely". Qatadah said that it means "those who learn the lessons". And Muqatel said that it means "those who reflect". There is no contradiction or apparent incompatibility amongst these interpretations. For example, one who sees the ruins and houses of those who belied Allah's Messengers would receive insight, admonition and reflection.
Alllah, subhanahu wa ta`ala, says the following with the regards to the hypocrites, "Had He willed, We could have shown them to you and you would have known them by their marks, but surely you will know them by the lahn of the speech!" [47:30]
The first thing mentioned is the firaasah of the eye and watching and the second thing noted is the firaasah of the ear and hearing. The lahn of their speech is namely two varieties. One is proper and the other is wrong.
The proper lahn may mean eloquence as stated in the hadeeth: "And perhaps some of you are more eloquent in their claim than others." (Bukhari and Muslim) Or it may mean an indirect reference or indication. The wrong lahn is the speech that has grammatical mistakes. By using it, people tend to change the meaning to something incorrect or to a hidden meaning which may not have been intended.
The meaning of the verse is that Allah has confirmed to His Prophet, sallallahu `alayhe wa sallam, that he would know them from the lahn of their speech. It is more likely that one may know more about the speaker and what is within his mind from his speech and the tone of his voice than from his physical appearance. The words and the tone of voice can tell much more, than the appearance, about the intention of the speaker. Firaasah can be either visual or auditory. The Prophet, sallallahu `alayhe wa sallam, is reported to have said, "Beware of the firaasah of the believer, for he sees with the light of Allah," then he recited the verse, "Surely! In this are the signs for the mutawassimeen." [15:75] (Tirmidhi) The firaasah of the believer is always truthful.
The firaasah is a light which Allah, subhanahu wa ta`ala, deposits in the heart of His servant. By this light, His servant distinguishes between truth and falsehood and between right and wrong.
The reality of firasah is a sharp thought that enters the heart and dominates its opinion. It overwhelms the heart just as the lion does to its pray, fareesah. Note the similarity between firaasah and fareesah in Arabic. However, in their linguistic forms, fareesah is an object whereas firasah is similar in form to wilaayah (authority and power), imaarah (authority and command) and siyaasah (administration and leadership).
The strength of firaasah is dependent on the strength of faith. A person with stronger faith has sharper firaasah. Amr bin Nujaid said that Shah al-Kermani had sharp firaasah and was never wrong. He also used to say that whoever lowers his gaze away from prohibitions, restrains himself from vain desires, constructs his interior according to muraaqabah (knowledge that Allah is watching over us), his exterior according to the Sunnah, and accustoms himself to eat only halaal, his firaasah will never be wrong.
Ibn Masoud said,
"There are three people with the sharpest firaasah. The Egyptian who bought Yusuf and then said to his wife, 'Make his stay comfortable, maybe he will profit for us or we shall adopt him as a son.' [12:21]. The other was the daughter of Shuaib, who said to her father with regards to Musa, 'Hire him!' [28:26] And Abu Bakr, for he appointed Omar as his successor."
Another narration includes the wife of Pharaoh who said about Musa, "A comfort of the eye for me and for you. Kill him not, perhaps he may be of benefit to us, or we may adopt him as a son.' [28:9]
Abu Bakr As-Siddeeq is considered to be the one with the greatest firasah in the ummah and Umar was the second. The incidents that prove Umar's firasah are numerous, familiar and well-known. He never said with regards to anything, "I think this is so," but it was what he thought. The fact that the Quran approved of his opinions in many incidents is sufficient evidence of his sharp firaasah. One of which was his opinion regarding the redemption of the captives from the Battle of Badr.
Once a man named Sawad Bin Qarib passed by and Umar dind't know him. Umar said,
"This is either a soothsayer or he was so in the days of jahiliyyah."
Upon sitting before Umar, Sawad said, "O commander of the faithful! You never received any of your guests the way you did me." Umar said,
"What we used to do in the days of jahiliyyah is worse than this. But tell me about what I have asked you."
Sawad said, "You were true, O commander of the faithful! I was a soothsayer in the days of jahiliyyah, then he told him the story."
The sahabah, in general, had the most accurate and sharpest firaasah. The true firaasah is obtained from life and from the light Allah grants to whom He wishes from amongst His true servants. The heart receives life and light and then its firaasah will almost never be wrong. Allah says, "Is he who was dead and We gave him life and set for him a light whereby he can walk amongst men, like him who is in the darkness from which he can never come out?" [6:122]
The verse describes the person as "dead" because of the disbelief in his heart and the life of jahiliyyah or ignorance he was leading, but then Allah gave him life through emaan or faith of knowledge. Upon his acceptance of these gifts, the Qur'an and faith become the light by which he sees his way out of the darkness (of disbelief and ignorance) and onto the straight path.
Firaasah is linked to three human organs: the eye, ear and heart. His eye examines the look and the signs, his ear examines the speech, the over expressions, oblique inferences and hints, content, logic and tone of voice. And his heart analyzes both what is seen and hear to perceive hidden thoughts of others. His analysis and examination of the interior compared to the exterior is like one who examines currency to see if it is counterfeit after examining the outside. It is also similar to Ahlul-Hadeeth (scholars who specialize in the knowledge of the hadeeth), who will read a hadeeth that has a sound isnaad (chain of narrators) but upon examination of the matn (text of the hadeeth), it is found that it is a fabricated hadeeth.
There are two factors in firaasah. One is the quality of one's mind, the sharpness of the heart and the intelligence. The second is the appearance of the signs and indications on others. When both factors are present than one's firaasah may not be wrong. Iyaas bin Mu`awiyah had great firaasah and he was well-known because of it, as was Imaam Shaafi'ee who was also reported to have written about it.