Sayyiduna Ibn Umar (may Allah be pleased with them both) narrates: "I heard the Messenger of Allah (peace and blessings be upon him) saying: 'The best worship is understanding of the religion (fiqh), and the best religiousness is scrupulous piety (wara').'"
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from al-Sha'bi except Ibn Abi Layla, and no one from Ibn Abi Layla except Khalid, and Sulayman bin Abd al-Rahman is alone in narrating it."
Hadith Referenceالمعجم الأوسط / باب الواو / 9264
Hadith Takhrij«أخرجه الطبراني فى «الكبير» برقم: 13706، 13922، والطبراني فى «الصغير» برقم: 1114»