Markandeya Purana, Canto 25 to 30,
The story is that of Madalasa who was a Self realised Queen who gave birth to a child. When the child cried, instead of diverting the child's attention with various objects she chose to introduce him to the truth. And that truth is sung in the form of a sweet lullaby which is called madalasa upadesha or madalasa putra upadesha.
शुद्धोसि बुद्धोसि निरँजनोऽसि
सँसारस्वप्नँ त्यज मोहनिद्राँ
Madalasa says to her crying son:
You are pure, Enlightened, and spotless.
Leave the illusion of the world
and wake up from this deep slumber of delusion.
शुद्धोऽसि रे तात न तेऽस्ति नाम
कृतँ हि तत्कल्पनयाधुनैव।
पच्चात्मकँ देहँ इदँ न तेऽस्ति
नैवास्य त्वँ रोदिषि कस्य हेतो॥
My Child, you are Ever Pure! You do not have a name. A name is only an imaginary superimposition on you.
This body made of five elements is not you nor do you belong to it. This being so, what can be a reason for your crying ?
न वै भवान् रोदिति विक्ष्वजन्मा
शब्दोयमायाध्य महीश सूनूम्।
गुणाश्च भौताः सकलेन्दियेषु॥
The essence of the universe does not cry in reality. All is a maya of words, oh Prince! Please understand this. The various qualities you seem to have are are just your imaginations, they belong to the elements that make the senses (and have nothing to do with you).
भूतनि भूतैः परिदुर्बलानि
वृद्धिँ समायाति यथेह पुँसः।
न तेस्ति वृद्धिर् न च तेस्ति हानिः॥
The Elements [that make this body] grow with accumulation of more elements or reduce in size if some elements are taken away. This is what is seen in a body's growing in size or becoming lean depending upon the consumption of food, water etc. You do not have growth or decay.
त्वम् कँचुके शीर्यमाणे निजोस्मिन्
तस्मिन् देहे मूढताँ मा व्रजेथाः।
मृदादिभिः कँचुकस्ते पिनद्धः॥
You are in the body which is like a jacket that gets worn out day by day. Do not have the wrong notion that you are the body. This body is like a jacket that you are tied to, for the frutification of the good and bad karmas.
तातेति किँचित् तनयेति किँचित्
अँबेति किँचिद्धयितेति किँचित्।
ममेति किँचित् न ममेति किँचित्
त्वम् भूतसँघँ बहु म नयेथाः॥
Some may refer to you are Father and some others may refer to you a Son or
some may refer to you as mother and some one else may refer to you as wife.
some say you are mine and some others say you are not mine
These are all references to this Combination of Physical Elements, Do not identify with them.
सुखानि दुःखोपशमाय भोगान्
सुखाय जानाति विमूढचेताः।
तान्येव दुःखानि पुनः सुखानि
The deluded look at objects of enjoyments as giving happiness by removing the unhappiness. The wise clearly see that the same object which gives happiness now will become a source of unhappiness.
यानँ चित्तौ तत्र गतश्च देहो
देहोपि चान्यः पुरुषो निविष्ठः।
ममत्वमुरोया न यथ तथास्मिन्
देहेति मात्रँ बत मूढरौष।
The vehicle that moves on the ground is different from the person in it similarly this body is also different from the person who is inside!
The owner of the body is different from the body! Ah how foolish it is to think I am the body!
Here is the 'link' where it has been sung beautifully