In meaning, it signifies presence (being in the presence of Allah). It is a ḥāl (spiritual state) close to ʿilm al-yaqīn (knowledge of certainty) and its realities.
The people of mushāhada (the people of spiritual witnessing) are of three degrees: The first degree is the mushāhada of the murīds (aspirants, also called aṣāghir). Abū Bakr Wāsiṭī expresses their mushāhada as follows: They witness things with the eye of reflection, contemplating with the eye of thought. The second degree is the mushāhada of the khawāṣṣ (the elect, also called awsaṭ). Abū Saʿīd Ḥarrāz describes them thus: People are in the hand and dominion of the Real (al-Ḥaqq). The state of mushāhada that occurs between Allah and the servant leaves nothing in the servant’s secret or imagination except Allah. The third degree of mushāhada is that of the ʿārifūn (gnostics). ʿAmr ʿUthmān al-Makkī, in his Kitāb al-Mushāhada, alludes to this: When the hearts of the ʿārifūn are firmly established in mushāhada, they witness Him in everything. They witness the entire cosmos through Him. Their witnessing is in His presence and with Him. They pass from the ḥāl (spiritual state) of ghayba (absence) to the state of presence, and from the state of presence to the state of ghayba. In both states, they perceive the oneness of the Real (al-Ḥaqq). Thus, the outward and the inward, the inward and the outward, the last and the first, the first and the last—all witness Him (in every conceivable hidden and manifest, prior and subsequent state, they witness Him and see nothing else). (Lumaʿ, 101)
Yaqīn (certainty) is mukāshafa (unveiling). There are three types of mukāshafa: The first is the unveiling seen with the eye on the Day of Qiyāma (Resurrection); the second is the unveiling by which hearts, in a manner indescribable, discover the realities of faith (īmān) through attendance, unveiling, and witnessing via the path of yaqīn; the third is the unveiling of miracles to prophets through the manifestation of qudra (divine power), and to non-prophets through karāma (saintly wonders) and answered prayers (ijāba). (Lumaʿ, 102)
The state of mushāhada and kurb is as follows: The servant, with certain knowledge, ascends to the purity (ṣafā) of the qalb (heart). The ṣafā of the qalb raises the servant to the stations of witnessing with the eye, so that nothing passes through his qalb except the thought of the Real (al-Ḥaqq). If he were to disobey, it would be as if he disobeyed the Real. Neglecting or ignoring this brings sorrow (turbidity) to the qalb. The sorrow of the qalb means its darkening. This is the maqām (spiritual station) of the qalb at the point of qaswa (hardness). These stations are the beginning of buʿd (distance).
I heard the following: For every deed, even a small one, three registers are opened. The first is the register of 'why'. The second is the register of 'how'. The third is the register of 'for whom'. 'Why?' means: why did you do it? This is the station of ubūdiyya (servitude) and a place of trial deriving from the attribute of rubūbiyya (lordship). That is, did you do it for your Lord or for the desire of your nafs (lower self)? If one fulfills what is required as commanded by his Lord and is saved from this register, then the question of the second register is asked: How did you do it? This is the place of questioning by knowledge, the second imtihān (test). That is, you did what you had to do, but did you do it knowingly or unknowingly?
Allah, Exalted is He, does not accept an action performed not in His path and not according to the requirements of knowledge. If one is saved from this register as well, a third register is opened and he is asked: For whom? This path is the path of worship (taʿabbud) with ikhlāṣ (sincerity) for the riḍā (contentment) of rubūbiyya. This is the third imtihān (test). (Kūt, I, 80)
Mushāhada that allows seeing the unseen with the eye of yaqīn is called khawāṭir (passing thoughts). These are either from the nafs, or from the enemy (shayṭān) due to envy, or a 'hems' (whisper) from an angel. (Kūt, I, 126)
First comes muḥāḍara (presence), then mukāshafa (unveiling), and then mushāhada (witnessing). Muḥāḍara is the presence of the qalb. Sometimes muḥāḍara occurs through the accumulation of proofs. Even if this arises from the dominance of the power of dhikr (remembrance), it comes after the state of satr (veiling). After this, the state of kashf (unveiling) occurs. The state of muḥāḍara is the presence of the qalb through the attribute of bayān (clear exposition). In this state, there is no need for seeking proof, searching for a way, or being veiled by doubts or the attribute of the unseen.
After muḥāḍara comes the state of mushāhada. Mushāhada is the presence of the Real in the qalb without any doubt. When the clouds of satr (veiling) are dispersed from the sky of the qalb and rūḥ (spirit), the sun of mushāhada begins to shine in the constellation of honor (i.e., when the qalb is purified and freed from veils, witnessing the ḥaqīqa (inner reality) becomes possible).
The reality of mushāhada is explained by the saying of Junayd: 'Mushāhada is finding the Real by annihilating (fanāʾ) oneself.' In this ḥāl (state), the possessor of muḥāḍara is attached to the proofs of Allah; the possessor of mukāshafa is in the state of expansion (bast) through His attributes; the possessor of mushāhada has attained His Essence.
muḥāḍara-mukāshafa-mushāhada
The intellect leads the possessor of muḥāḍara to hudā (guidance). The actions of the possessor of mukāshafa draw him near to Allah. The possessor of mushāhada attains the secret of maʿrifa (gnosis) of annihilation (fanāʾ, self-effacement)... (Qushayrī, 43; Jāmiʿ, 253)
One who possesses the knowledge of yaqīn does not fall into doubt in the sense used by the scholars, nor in an absolute sense. Since it does not occur in the scriptural texts, the term yaqīn is not used as an attribute of Allah. ʿIlm al-yaqīn, ʿayn al-yaqīn, and ḥaqq al-yaqīn are all forms of yaqīn itself. According to the terminology of the Sufis, ʿilm al-yaqīn is knowledge obtained by proof and evidence. ʿAyn al-yaqīn is knowledge that is manifest (in the ruling of bayān). Ḥaqq al-yaqīn is direct witnessing.