What is the meaning of "Al-Urwah Al-Wuthqa" (the Most Trustworthy Handhold) mentioned in the Holy Qur'an?

The phrase "al-urwat al-wuthqa" (the most trustworthy handhold) is mentioned in two places in the Quran: Surah Al-Baqarah (2:256) and Surah Luqman (31:22). Exegetes have interpreted it in several ways, including: "La ilaha illa Allah" (There is no god but Allah), faith, Islam, and the Quran. There is no contradiction between these interpretations, as they all point to adherence to the upright religion which grants stability and and security.