In Hujwiri's Kashf al-Mahjub, Abu Bakr al-Shibli is singled out for his isharat — subtle, elliptical allusions that gesture toward mystical meaning rather than stating it plainly. Hujwiri reports a later master ranking them among the three wonders of the world, alongside al-Murta'ish's fine points (nukat) and Ja'far's tales (hikayat).

As a concept, ishara names a recognized register of Sufi speech: meaning pointed at for the initiated, resisting literal paraphrase because ordinary language cannot hold direct spiritual experience. An example is al-Shibli's reading of the Quranic command to lower the gaze (qul li'l-mu'minina yaghuddu min absarihim), which he extends from the outward eyes of the head averting the forbidden to the inner eyes of the heart averting all but God.