ʿIlm al-sharīʿa (knowledge of the sharia) is a single science that encompasses both meanings known as riwāya (transmission) and dirāya (understanding), united under one name. When these are brought together, what emerges is a knowledge of the sharia that calls to both outward (ẓāhir) and inward (bāṭin) acts. In this sense, it is not possible to consider the outward and inward aspects of knowledge as separate from one another. This is because knowledge resides in the qalb (the heart), and if it is not expressed by the tongue, it is inward knowledge. When knowledge is manifested by the tongue, it becomes outward. For this reason, we do not say that knowledge is outward and inward. In reality, knowledge is the knowledge of the sharia that leads to and necessitates both outward and inward acts. Outward acts are those performed by the limbs, such as purification, prayer, zakat, fasting, pilgrimage, as well as legal penalties, divorce, manumission of slaves, commercial transactions, inheritance law, retribution, and similar rulings. All of these are outward actions performed with our bodies.
Inward acts, on the other hand, are affirmation, iman (faith), yaqīn (certainty), ṣidq (truthfulness), ikhlas (sincerity), maʿrifa (gnosis, experiential knowledge of God), tawakkul (reliance upon God), maḥabba (love), riḍā (contentment with God's decree), dhikr (remembrance of God), shukr (gratitude), ināba (turning to God), khashya (awe), taqwa (God-consciousness), murāqaba (spiritual vigilance), tafakkur (contemplation), iʿtibār (taking heed), khawf (fear), rajāʾ (hope), sabr (patient endurance), qanāʿa (contentment), taslīmiyya (submission), tafwīḍ al-umūr (entrusting affairs to God), qurb (nearness to God), shawq (longing), and wajd (ecstatic experience).