Sri Guru Granth Sahib bless Sikh with following knowledge about four phases of life. The metaphor used here compare four phases of life with four phases of night.
Let me give you an example so that ww can understand a new perspective to see and understand outer and inner perspectives of our understanding about any subject or point.
When we see color of leaves of trees, mostly it is green. Lets see why we see green whereas surrounding air has no colour. When we see air it means we are seeing through air because air is transparent. It means air is the media for our eyes through which we see all the rainbow colors.
Our ability to see through transparent air is due to presence of light in air. If there is no light in air, it would be pitch dark. When we see tree leaves and (say) we see it green.
Light is transparent in nature if there is no object in air then air always looks transparent and we can see through.
But light is composed of rainbow colors. When we split light we get all seven colors of light. When all seven colours are combined together then they are transparent and light shows no colour.
Then why tree leaves looks green only? As we understood in past paragraph that light has seven colors. When light strikes the tree leaves, the leave absorb six colours out of seven and use energies of six colours to feed itself. But green leaves do not like green colour energy and it does not absorb it. As a result it reject the green colour energy. So green colour energy get reflected back which our eyes receives after light strikes with leaves.
Don't think too much if Physics is not your favourite subject. But whole idea to discuss light and its seven colours is to give you understanding why things have different colours. Any colour which is not accepted by the object, the object looks like of that colour.
So lets say tree leaves are green. It simply means that tree leaves did not like the green colour and rejected that colour. And that rejected colour represent the leave as its colour. Whereas truth is green tree leaves looks green because they do not like green colour energy to absorb.
So a green colour tree leave grows by absorbing six colours energy from light. Green leave won't grow if it absorbs green light energy.
So green leaves tricked us. Out of seven colours green leaves absorb/accept/take all other six colours energies to grow except green.
So we can say a green leave is really surviving based on six colours' energies except green colour energy.
Further when we see a tree from a distance, the various reflected lights from tree only enters our eye and those reflected light colours by tree makes an image of the tree in our eye.
Another important hidden virtue of nature is very important to understand about our vision. When we see tree the reflected colour light when enter our eye it forms an image. But remember after light enters our eye it is inverted light. It means tree trunk would enter in our eye to the top of our eye retina and top of tree light would enter to the bottom of retina.
Then why tree does not look inverted through our vision.
There are two possibilities:
1 Lets say the inverted light image of tree is the final image processed by our eyes, then it clears means every thing we see through our eyes in reality is inverted. I mean every thing is upside down. What do you think?
2 Second possibility is that tree is not inverted but as image formation of tree in our eye inverts the light to form a image in reality. Then it means after image is formed in our eye about the tree which is inverted, the image is reinverted again before our mind acknowledge it as real image. So when eye sees the outer world it sees the world image as upside down (inverted) but then our brain has built in mechanism which reinvert the image to make it straight as we actually perceive.
So now you know three interesting natural phenomenas about light, light reflection to our eye as inverted, our brain reinvert the image to make it straight.
From now onwards you can understand and interpret phenomena of light, its colours and our perception and reception of images.
Guru Nanak want us to understand life through same lens. Our life without knowledge of Our One Universal Master and without acknowledging that One Master as source and cause of life means we are looking at world without reinverting the world images. Which is not true. Same is the true in Guru Nanaks eyes that invisible power of Our One Universal Master when strikes upon us the absorbed part of that invisible power is our real source of existence and not our perception which is based on reflected colours. So instead of focusing on green colour, focus on six non-green colours which empowers the existence of green leaves.
ਪਹਿਲੈ ਪਹਰੈ
ਰੈਣੀ ਕੈ ਵਣਜਾਰਿਆ ਮਿਤ੍ਰਾ ਹਰਿ ਪਾਇਆ ਉਦਰ ਮੰਝਾਰਿ ॥
ਦੂਜੇ ਪਹਿਰੈ ਰੈਣਿ ਕੈ ਵਣਜਾਰਿਆ ਮਿਤ੍ਰਾ
ਮਨੁ ਲਾਗਾ ਦੂਜੈ ਭਾਇ ॥
ਤੀਜੈ ਪਹਿਰੈ ਰੈਣਿ ਕੈ ਵਣਜਾਰਿਆ ਮਿਤ੍ਰਾ ਮਨੁ ਲਗਾ ਆਲਿ ਜੰਜਾਲਿ ॥
ਚਉਥੈ
ਪਹਿਰੈ ਰੈਣਿ ਕੈ ਵਣਜਾਰਿਆ ਮਿਤ੍ਰਾ ਹਰਿ ਚਲਣ ਵੇਲਾ ਆਦੀ ॥
