"Do not be importunate in asking (for something), for by Allah, if one of you asked me for something and I gave it to him while I am reluctant, there will be no blessing in what I gave him." [Muslim]
Original Hadith
«لا تُلْحِفُوا في المسأَلة، فوالله لا يَسْألني أحدٌ منكم شيئًا، فَتُخْرِجَ له مسألته منِّي شيئًا وأنا له كارِهٌ، فيُبَارَك له فيما أَعْطَيتُه»
رواه مسلم