In Islam, "lawful sustenance" (Rizq Halal) refers to securing one's livelihood through legitimate means in accordance with divine commands. The Holy Quran repeatedly emphasizes its importance, presenting it not merely as a tool for meeting material needs, but as a key factor for blessings in life and for drawing closer to God. Earning lawful sustenance is a fundamental condition for improving individual and social well-being and paves the way for positive worldly and otherworldly effects. This research, using a descriptive-analytical approach and relying on Quranic sources, authentic exegeses (tafsir), and traditions of the Ahl al-Bayt (peace be upon them), examines the effects of lawful sustenance. In the worldly dimension, results indicate that lawful sustenance ensures the improvement of an individual’s economic and spiritual status by influencing blessings in wealth, physical and mental health, and the creation of peace of mind. In the otherworldly dimension, this research further explains that seeking lawful sustenance protects the individual from divine punishment and facilitates the attainment of immense rewards in the Hereafter. Finally, adhering to the principles of lawful sustenance not only strengthens faith and piety in the present life but also paves the path to eternal felicity. This research proves that lawful sustenance is a comprehensive solution for human transcendence in both worlds.