The Quran repeatedly talks about how believers are mindful of their duty, but what does this mean. Is akhlaq the duty, plus the prayers and other pillars?
("Remember"is also translated in some places as "mindful". In fact the word dhikr is throughout the Quran is translated as remembrance sometimes but often also as mindfulness.)
Possible meanings in terms of Buddhism
Does it mean to be mindful while praying and going about the day to day world? Or does it mean to remember to pray? The concept of kushoo definitely is relevant here, mindfulness during prayer.
Hypocrites are people who pray lazily, without any true effort, just to check off the boxes and have their religious legitimacy paperwork signed off on. So mindful of their duty would mean being careful and meticulous about one's intentions to draw closer to God and follow the Prophet (PBUH) and not just empty ritual that has no heart in it.
Being mindful of one's duty as a believer is also akhlaq and adab*, all the pieces that go into that, which I am woefully bad at as well and can't say much here other than it is a central piece of the puzzle. The manners, ethics, and comportment of the believer include the manners of the heart such as the four brahmaviharas. Love, compassion, equanimity, and sympathetic joy.
Being mindful of one's duty is also to be grateful to God as we are encouraged to be grateful in the Quran so many times. This involves noting and contemplating the signs in nature and the world, and cultivating a grateful heart.
The contemplation of signs is connected to Right Understanding and insight into the nature of things. The Prophet (PBUH) said to the companions "an hour of contemplation is worth seventy years of worship". These two sayings direct the believer to the same action.
