Matmonim: Daf Yomi by Rabbi David Lapin

Nedarim 50b-51a Service with a Smile? Maybe not! - עבדו את ה' בשמחה

Since after the destruction of the second Beit Mikdash there have been two schools of thought about whether to focus our service of  Hashem with joy or with seriousness. What is the real issue? 
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