Tafsir of Al-Baqarah 2:103

And how bad indeed was that for which they sold their own selves, if they but knew. And if they had believed and guarded themselves from evil and kept their duty to Allah, far better would have been the reward from their Lord, if they but knew! Allah stated,

ولبيس

(And how bad) meaning, what they preferred, magic, instead of faith and following the Messenger, if they but comprehend the advice

ولو أنهم آمنوا واتقوا لمثوبة من عند الله خير

And if they had believed and guarded themselves from evil and kept their duty to Allah, far better would have been the reward from their Lord, meaning, "Had they believed in Allah and His Messenger and avoided the prohibitions, then Allah's reward for these good deeds would have been better for them than what they chose and preferred for themselves.'' Similarly, Allah said,

وقال الذين أوتوا العلم ويلكم ثواب الله خير لمن ءامن وعمل صلحا وﻻ يلقاها إﻻ الصبرون

But those who had been given (religious) knowledge said: "Woe to you! The reward of Allah (in the Hereafter) is better for those who believe and do righteous good deeds, and this none shall attain except As-Sabirun (the patient in following the truth).'' (28:80)