لَا يُؤْمِنُ أَحَدُكُمْ حَتَّى يَكُونَ هَوَاهُ تَبَعًا لِمَا جِئْتُ بِهِ
None of you attains the intended completeness of faith until their desires follow what I have brought.
Source: الدارمي
هَوَاهُ denotes a person’s inclination or desire, while تَبَعًا means following or being subordinate. لِمَا جِئْتُ بِهِ means “to what I have brought.” Having preferences is not forbidden; the point is what guides a person when personal wishes conflict with the Prophet’s teaching.
In لَا يُؤْمِنُ, لَا negates the present-tense verb يُؤْمِنُ. حَتَّى introduces the required condition. Read this as a call to improve conduct, not as grounds for casually judging a particular person’s faith.