Certainty of knowledge (yaqin) has been described as having three stages:
Certainty of mind
Certitude of knowledge or certainty of mind (‘Ilm-ul-yaqin) which is the Faith that a person obtains by various means such as the one who sees smoke and believes there is fire there.
Certainty of Sight
Certainty of Sight (‘Iym-ul-yaqin) which is what one sees with one’s eyes; for instance, one sees the fire, himself.
The absolute truth of assured certainty
The absolute truth of assured certainty (Haqq-ul-yaqin) which means the ‘realization’ or the ‘knowledge proper’. It is the personal experience as when the one who arrives in the fire oneself and feels the heat of it and takes the attributes of fire into his entity. This very state is the highest degree of ‘yaqin’.
In fact, the first stage is general; the second stage is for pious people; and the third stage is for those who are in some way chosen above others.
A tradition from the Holy Prophet (S) denotes that some people asked him about a matter that they had heard about some of the companions of Prophet Jesus (as) who used to walk on water, and he (S) said:
“If their certitude was in a highest position they could walk in the air.”
The late ‘Alamah Tabatabai, after mentioning this tradition, adds that everything pivots on the certitude to Allah, the Glorified, and to know no other means of the effects of this world, but Allah. Therefore, the more the Faith and certainty, in a person, is the absolute power of Allah, the more objects, in this world, will be obedient to him.
And this is the secret of the relation of certitude (yaqin) and the ‘extraordinary interference’ in the world of creation.