Hasan on Mindfulness: Presence of heart required in every prayer

Rabia’ ibn Subayh reported: Al-Hasan al-Basri, may Allah have mercy on him, said, “Every prayer in which your heart is not present may more quickly be punished than rewarded.”

Source: al-Arba’ūn lil-Ṭūsī 11

عَنِ رَبِيع بْن صُبَيْحٍ عَنِ الْحَسَنِ البصري قَالَ رحمه الله كُلُّ صَلَاةٍ لَا يَحْضُرُهَا قَلْبُكَ فَهِيَ إِلَى الْعُقُوبَةِ أَسْرَعُ مِنْهَا إِلَى الثَّوَابِ

11 الأربعون لمحمد بن أسلم الطوسي