وَلَعَبْدٌ مُّؤْمِنٌ خَيْرٌ مِّن مُّشْرِكٍ وَلَوْ أَعْجَبَكُمْ
Meaning: And a believer is better than a mushriq ( a polytheist ) even if he amazes you.
Annotation: Muslim is an Arabic word. The person who surrenders on Allahu tawala is regarded as a muslim. A pure muslim follows the instructions of the Quran.

Every pain removes the sins of a muslim

وَعَن أبي هُرَيْرَة وَأبي سَعِيدٍ عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «مَا يُصِيبُ الْمُسْلِمَ مِنْ نَصَبٍ وَلَا وَصَبٍ وَلَا هَمٍّ وَلَا حُزْنٍ وَلَا أَذًى وَلَا غَمٍّ حَتَّى الشَّوْكَةُ يُشَاكُهَا إِلَّا كَفَّرَ اللَّهُ بهَا من خطاياه»
مُتَّفق عَلَيْهِ (الألباني) :حكم
Meaning: He and Abu Sa'id reported the Prophet as saying, “When a muslim falls in difficulty, continuous pain, anxiety, grief, injury, or care, or even by a thorn with which he is pierced, Allah jalla jalaaluhu thereby removes his sins.” Bukhari and Muslim
Reference : Mishkat al-Masabih 1537 In-book reference : Book 5, Hadith 15

One can attain the rewards like the person who performs fasting and performs the salah during night showing good bahaviour:

وعن عائشة رضي الله عنها، قالت‏:‏ سمعت رسول الله صلى الله عليه وسلم يقول‏:‏ “ إن المؤمن ليدرك بحسن خلقه درجة الصائم القائم
(‏رواه أبو داود‏)
Meaning:
Aishah (May Allah be pleased with her) reported: I heard Messenger of Allah (ﷺ) saying: "A believer will attain by his good behaviour the rank of one who prays during the night and observes fasting during the day."
Abu Dawud
Reference : Riyad as-Salihin 628 In-book reference : Introduction, Hadith 628

The muslims are like brothers

إِنَّمَا الْمُؤْمِنُونَ إِخْوَةٌ فَأَصْلِحُوا بَيْنَ أَخَوَيْكُمْ ۚ وَاتَّقُوا اللَّهَ لَعَلَّكُمْ تُرْحَمُونَ
الحجرات: 10
Meaning:
The believers are nothing else than brothers (in Islamic religion). So make reconciliation between your brothers, and fear Allah, that you may receive mercy.
Al Hujuraat: 10