What is the greatest of all good deeds in Islam?

After belief in Allāh, the greatest of good deeds in Islam is jihād (striving in the path of Allāh). It is reported in the authentic ḥadīth that the Prophet (PBUH) was asked, “Which is the best deed?” He replied, “To believe in Allāh and His Apostle (Muḥammad).” He was then asked, “What is next?” He said, “To participate in jihād.”¹ Jihād is ḏirwat sanām al-Islām (lit. the top of Islam’s hump, meaning its peak). The Prophet Muḥammad (PBUH) said, “The head of the matter is Islam, its pillar is prayer, and the top of its hump is jihād.”² Jihād is the greatest trade with Allāh—one that will never fail, that secures for a person what they seek, and protects them from what they fear: {O believers! Shall I guide you to an exchange that will save you from a painful punishment? ˹It is to˺ have faith in Allāh and His Messenger, and strive in the cause of Allāh with your wealth and your lives. That is best for you, if only you knew. He will forgive your sins, and admit you into Gardens under which rivers flow, and ˹house you in˺ splendid homes in the Gardens of Eternity. That is the ultimate triumph. ˹He will also give you˺ another favor that you long for: help from Allāh and an imminent victory. ˹So˺ give good news ˹O Prophet˺ to the believers} (Qurʾān 61:10–13). Indeed, jihād is the most profitable commerce.