What is meant by "knowledge" in the noble Hadith, "The best of you is he who learns the Qur'an and teaches it"? Is it learning the Qur'an, Tajweed, and the rules of recitation, or learning the interpretation of the Qur'an?

The Hadith is authentic, and its meaning is that the best of people is he who learns the Qur'an and teaches it, through memorization, recitation (tajweed), and interpretation, by encompassing the Islamic sciences. This person is complete in himself and completes others, thus he is the best of believers. It was narrated from Jesus, peace be upon him, that whoever learns, practices, and teaches will be called great in the heavens. Abu Abd al-Rahman al-Sulami explained this as the reason that led him to dedicate himself to teaching people the Qur'an.