Explanation of "The Tree of Faith" Imaam Abdur Rahmaan as-Sa'dee by Abdur - Ra'uf Shakir Ibn Taymiyyah writes:
وَمَعْلُومٌ أَنَّ الْإِيمَانَ هُوَ الْإِقْرَارُ لَا مُجَرَّدُ التَّصْدِيقِ وَالْإِقْرَارُ ضِمْنَ قَوْلِ الْقَلْبِ الَّذِي هُوَ التَّصْدِيقُ وَعَمَلِ الْقَلْبِ الَّذِي هُوَ الِانْقِيَادُ
It is understood that faith is affirmation and not merely belief. Affirmation includes the words of the heart, which is belief, and the actions of the heart, which is compliance.
Source: Majmu’ Al-Fatawa 7/638
“I am the One, One Who does not stand in need of a partner. If anyone does anything in which he associates anyone else with Me, I shall abandon him with one whom he associates with Allaah.” Reported in Saheeh Muslim, (English translation no. 7114, book 42)