قُلْ إِن كُنتُمْ تُحِبُّونَ اللّهَ فَاتَّبِعُونِي يُحْبِبْكُمُ اللّهُ وَيَغْفِرْ لَكُمْ ذُنُوبَكُمْ وَاللّهُ غَفُورٌ رَّحِيمٌ
Say (O Muhammad SAW to mankind): "If you (really) love Allah then follow me (i.e. accept Islamic Monotheism, follow the Quran and the Sunnah), Allah will love you and forgive you of your sins. And Allah is Oft-Forgiving, Most Merciful."
Aal-e-Imran سورة آل عمران 3:31
وَقَالَ رَبُّكُمُ ادْعُونِي أَسْتَجِبْ لَكُمْ إِنَّ الَّذِينَ يَسْتَكْبِرُونَ عَنْ عِبَادَتِي سَيَدْخُلُونَ جَهَنَّمَ دَاخِرِينَ
And your Lord said: "Invoke Me, (i.e. believe in My Oneness (Islamic Monotheism)) (and ask Me for anything) I will respond to your (invocation). Verily! Those who scorn My worship (i.e. do not invoke Me, and do not believe in My Oneness, (Islamic Monotheism)) they will surely enter Hell in humiliation!"
Ghafir سسورة غافر 40:1
يَا أَيُّهَا النَّاسُ قَدْ جَاءتْكُم مَّوْعِظَةٌ مِّن رَّبِّكُمْ وَشِفَاء لِّمَا فِي الصُّدُورِ وَهُدًى وَرَحْمَةٌ لِّلْمُؤْمِنِينَ
O mankind! There has come to you a good advice from your Lord (i.e. the Quran, ordering all that is good and forbidding all that is evil), and a healing for that (disease of ignorance, doubt, hypocrisy and differences, etc.) in your breasts, - a guidance and a mercy (explaining lawful and unlawful things, etc.) for the believers.
I heard the Prophet saying, "Ascribing false things to me is not like ascribing false things to anyone else. Whosoever tells a lie against me intentionally then surely let him occupy his seat in Hell-Fire." I heard the Prophet saying, "The deceased who is wailed over is tortured for that wailing."
Bukhari BOOK 23: Funerals (Al-Janaa'iz)