Is a Muslim's memorization of the Quran an indication of his righteousness and piety?

Whoever Allah makes it easy for to memorize the Quran has been given much good. The Messenger of Allah, peace and blessings be upon him, said: "The best among you is he who learns the Quran and teaches it," and he said: "Recite the Quran, for it will come as an intercessor for its companions on the Day of Resurrection," and he said: "Indeed, Allah raises some people by this Book and lowers others by it." However, memorizing the Quran does not necessarily indicate righteousness and piety. It has been narrated from the Prophet, peace and blessings be upon him, that the Quran will come on the Day of Resurrection as an adversary to whoever disobeys its commands and neglects its obligations, and as an intercessor for whoever upholds its limits and acts upon its obligations. It has also been reported that in the End of Time, there will be people who recite the Quran, but it will not go beyond their throats, and they will deviate from the religion.