The Method of Da'wah for Those Influenced by a Specific Culture

Question: If the people being invited are influenced by specific cultures or specific societies, what is the way to invite them?

Answer: He should explain to them the falsehood present in the schools of thought they were influenced by and the environment they were influenced by. He should clarify to them that these schools of thought contain such and such, and make clear the types of falsehood and religious innovations contained in them, if that is the case. He should explain to them that the reference for all matters is the Book of Allah (Mighty and Majestic) and the Sunnah of His Messenger (peace and blessings be upon him). Therefore, whatever you have obtained from such and such, whatever you have learned from such and such, and whatever character traits you have adopted due to the environment—such as free mixing of men and women—you must weigh that against the Shari'ah standard, just as scholars weigh fiqh issues against the Shari'ah evidence. Whatever agrees with it must be kept, and whatever contradicts it must be discarded, even if it comes from the customs of fathers, ancestors, shaykhs, or others.
In summary: It is obligatory to adhere to good character and the noble conduct indicated by the Book of Allah and the Sunnah of His Messenger (peace and blessings be upon him). One should not be biased toward the conduct of his father, grandfather, his own environment, or the environment of his country. Rather, he must adhere to the truth indicated by the Book of Allah (Mighty and Majestic), the Sunnah of His Messenger (peace and blessings be upon him), and the consensus of the Salaf of the Ummah.