It is narrated from Sayyiduna Wathilah bin al-Asqa' (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever attains knowledge will have two shares of reward, and if he could not attain knowledge, he will have one reward."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب آداب القاضي / 20369