Vivekachudamani 22

virajya viÿaya vratad dosa drsaya muhurmuhuh | 
svalaksye niyata vastha manasah sama ucyate || 
(Sankaracarya's Vivekachudamani 22) 

 The tranquil state of mind when it rests constantly upon the contemplation of the goal after having again and again detached itself from material sense objects through a process of continuous observation of their defects is called Sama. 

The more you become attached to Lord Vasudeva... That is very psychological. If you become attached to something, you become detached to something else. Attachment, detachment cannot be. So more you become attached to Vasudeva, then more you become detached to this material world. Just like Dhruva Mahārāja said, svāmin kṛtārtho 'smi varaṁ na yāce: [Cc. Madhya 22.42] "My dear Lord, I am not hankering after any benediction. I am completely benediction. No more benediction. I have got everything. I have got You, Prabhu. So what do I want more?" Yaṁ labdhvā cāparaṁ lābhaṁ manyate nādhikaṁ tataḥ. If one gets Krishna's favor, what does he want more? He has got everything because the Lord is everything. That is where one sees everything sama or equal.