According to search-discovered classical Islamic scholarship, Dua (الدعاء), or supplication, is a profound act of worship ('ibadah) and the very essence of a believer's connection with Allah. Derived from the Arabic root meaning 'to call' or 'to summon', it is the intimate conversation where a servant expresses their needs, hopes, and dependence directly to their Creator. Ibn Kathir's analysis of Quran 2:186 emphasizes Allah's nearness and His promise to respond to the call of the supplicant. This is thematically echoed across over 100 Quranic verses, from the foundational plea for guidance in Surah Al-Fatiha to the heartfelt supplications of prophets like Ibrahim (as) and Musa (as) during their greatest trials. Al-Qurtubi discusses the legal and practical etiquettes (adab) of Dua, while spiritual authorities like Al-Ghazali and Ibn Qayyim detail the necessary inner state of sincerity, humility, and absolute trust (tawakkul). This synthesis establishes Dua not merely as a prayer of request, but as a fundamental pillar of faith (iman) that acknowledges divine sovereignty and strengthens the spiritual heart.