This paper analyses the relationship between the means of perception and ishārī interpretation in al-Ḥakīm al-Tirmidhī's (d. 320/930) Bayān al-Farq. It is seen that al-Tirmidhī wrote this work within the framework of the issue of ‘How should the Qur'an be understood?’, which is one of the basic questions discussed in the formation process of Sufism. The author develops a different perspective on the subject in the history of Sufism by quoting verses from the Qur'an and associating the means of perception that he explains on the axis of the concept of “qalb” with Isārī interpretation. In this paper, the work is analysed through textual analysis within the framework of the question of what al-Tirmidhī aims with the connection between the levels of perception and Isārī interpretation, and al-Tirmidhī's theoretical approaches on this subject are evaluated. As a result of the textual analysis, the idea that the place of the science of signs and wisdom is the “qalb” comes to the fore in the connection that al-Tirmidhī establishes between the levels of perception and Isārī interpretation. The qalb as an instrument of perception and its degrees of “sadr, qalb, fuad and lubb” are explained in stages and it is stated that each centre of perception represents a different level of religious consciousness. The concepts of “Islam, faith, marifah and tawhid” are associated with these centres of perception and those who have knowledge are called “Muslim, mumın, arif and muwahhid”. The aim of al-Tirmidhī is to put forward the idea that one can comprehend the literal and spiritual meanings of the Qur'anic verses according to one’s level of perception and action. With this claim, he tried to justify the idea that verses have a spiritual meaning in addition to their literal meaning. Moreover, al-Tirmidhī, who constructed the first theory of the nafs in Sufism on the basis of this idea, defined the nafs as the opposite power of the qalb and regarded the qalb’s veiling from God as the greatest of calamities. As a matter of fact, the qalb, as a means of perception related to faith, is the place of tawhid and marifah. For this reason, he stated that Allah protects the qalbs of the people of tawhid. From such statements of al-Tirmidhī, it can be concluded that he was one of the authors who formed the earliest theoretical infrastructure in the field of al-Ishārī Tafsir. This article first analyses the focal concepts on which al-Tirmidhī based his thought in his work. Then, the theoretical approaches developed by al-Tirmidhī in the field of Ishārī exegesis are evaluated.