Hadith 1: Dont be a Ghali and dont be a Muqassir

Narrated that Prophet Muhammad (صلى الله عليه وآله) said as part of a hadith regarding Imam Ali (عليه السلام):

وسيهلك فيه اثنان ولا ذنب له: محب غال, ومقصر

"Regarding Him two groups of people will be destroyed - for no fault of His - an exaggerating lover (Ghali) and the one who falls short/reduces/lessens His rights (Muqassir)."

[Source: al-Amali, Shaikh Sadooq, Pg. 264]

Hadith 2: Who is a Ghali?

Part of a hadith as narrated from Abu Jafar Imam Baqir (عليه السلام):

 حُمَيْدُ بْنُ زِيَادٍ عَنِ الْحَسَنِ بْنِ مُحَمَّدِ بْنِ سَمَاعَةَ عَنْ بَعْضِ أَصْحَابِهِ عَنْ أَبَانٍ عَنْ عَمْرِو بْنِ خَالِدٍ عَنْ أَبِي جَعْفَرٍ (عَلَيهِ السَّلام) ...

 فَقَالَ لَهُ رَجُلٌ مِنَ الأنْصَارِ يُقَالُ لَهُ سَعْدٌ جُعِلْتُ فِدَاكَ مَا الْغَالِي قَالَ قَوْمٌ يَقُولُونَ فِينَا مَا لا نَقُولُهُ فِي أَنْفُسِنَا فَلَيْسَ أُولَئِكَ مِنَّا وَلَسْنَا مِنْهُمْ

A person from the Ansar (people of Medina) whose name was said to be Sa'd, said to the Imam, "May I be sacrificed for You, Who is a 'Ghali' ?

Imam (عليه السلام) said, "They are the people who say about Us what We do not say about Ourselves. So, they are not from Us and We are not from them."

[Source: al-Kafi, Vol. 2, Pg. 75]