Hadith 30, 40 Hadith an-Nawawi
On the authority of Abu Tha’labah al-Kushanee — Jurthoom bin Nashir (may Allah be pleased with him) — that the Messenger of Allah (peace and blessings of Allah be upon him) said:
Verily Allah ta’ala has laid down religious obligations (fara’id), so do not neglect them; and He has set limits, so do not overstep them; and He has forbidden some things, so do not violate them; and He has remained silent about some things, out of compassion for you, not forgetfulness — so do not seek after them.

A hasan hadeeth narrated by ad-Daraqutnee and others.
عَنْ أَبِي ثَعْلَبَةَ الْخُشَنِيِّ جُرْثُومِ بن نَاشِر رَضِيَ اللهُ عَنْهُ عَنْ رَسُولِ اللَّهِ صلى الله عليه و سلم قَال: "إنَّ اللَّهَ تَعَالَى فَرَضَ فَرَائِضَ فَلَا تُضَيِّعُوهَا، وَحَدَّ حُدُودًا فَلَا تَعْتَدُوهَا، وَحَرَّمَ أَشْيَاءَ فَلَا تَنْتَهِكُوهَا، وَسَكَتَ عَنْ أَشْيَاءَ رَحْمَةً لَكُمْ غَيْرَ نِسْيَانٍ فَلَا تَبْحَثُوا عَنْهَا". 
حَدِيثٌ حَسَنٌ، رَوَاهُ الدَّارَقُطْنِيّ ْ"في سننه" [4/184]، وَغَيْرُهُ.