According to search-discovered classical Islamic scholarship, the concept of al-Infāq (Spending) is a foundational pillar of faith and practice, signifying the circulation of divinely-entrusted wealth for the pleasure of Allah. Across more than 50 key verses, the Quran frames Infaq not as a financial loss, but as a spiritual investment and a means of purification (tazkiyah). Ibn Kathir's tafsir on verses like 2:261 highlights the divine promise of multiplying rewards up to 700 times or more, illustrating spending as a guaranteed transaction with God. Al-Qurtubi's juridical analysis distinguishes its forms, from obligatory Zakat to voluntary Sadaqah and familial provision (nafaqah). The linguistic root ن-ف-ق ('to exit'), as analyzed by scholars like Al-Tabari, implies that wealth is inherently transient and its true value is realized only when it 'exits' one's possession for a righteous cause. This comprehensive understanding, synthesized from numerous Quranic contexts, establishes Infaq as the primary mechanism for demonstrating gratitude, combating miserliness, ensuring social justice, and proving one's trust in Allah's ultimate provision.