There is a story in the Panchatantra, explaining the importance of Unity.
Once upon a time, a flock of doves, led by their King, Chitragreeva, spotted some grain spread under a Bunyan tree. They flew down to eat the grain, and were caught in a net that a hunter, who was hiding nearby, threw over them.
Chitragreeva advised them not to panic but to fly away all together, taking the net with them. They did so, landing at a place where Chitragreeva's friend, Hiranyaka, the mouse lived.
Hiranyaka gnawed through the net and set all the doves free. Thus the doves could successfully save themselves because they acted unitedly.
The following Subhaashit echos the teaching in this story-
अल्पानामपि वस्तूनां संहतिः कार्यसाधिका l
त्रृणैर्गुणत्वमापन्नैर् बध्यन्ते मत्तदन्तिनः ll
Great things can be achieved (कार्यसाधिका) if even insignificant or small (अल्पानामपि) things (वस्तूनां) are used together(संहतिः).
Many blades of grass woven together can make a rope (त्रृणैर्गुणत्वमापन्नैर्) capable of tying up (बध्यन्ते) an elephant in rut (मत्तदन्तिनः) (which has become extremely aggressive).
'United we stand- divided we fall'- This quote has been attributed to many statesmen of various countries- the first Prime Minister of India, Jawaharlal Nehru, has been said to have used it, too. He also described India as 'Unity in Diversity'.
Nowadays it appears that Indians remember only the diversity- of languages, of ethnicities, of traditions, and of geography. India has become a virtual political and social battlefield, with different groups of people fighting over myriad issues.
But we seem to have forgotten the unity- which should be strong because of our love for our motherland, because of our identity as Indians.
We find Indians justifying the secession of Indian states from the union. We find Indian citizens giving assistance to those who orchestrate terror attacks on our soil. We see insurgents murdering their own fellow countrymen. We find people of different religions demanding separate laws- laws which go against the principles laid out in our constitution.
Whatever our differences, whatever our problems, it is necessary for us not to lose our unity. Problems can be sorted out. But only if we stay united will it be possible for us to stand strong against any outside threat.
We should remember the story from the Mahabharat- the Pandavas received news that the Kauravas- their cousins- were losing the battle against the Gandharvas. Bhim was of the opinion that they should not help the Kauravas, who considered them their enemies. But Yudhishtir, the eldest Pandava, thought otherwise. He told the others-
परस्परविरोधे तु वयं पंचश्च ते शतम् l
परैस्तु विग्रहे प्राप्ते वयं पंचाधिकं शतम् ll
"If there is a quarrel between us (cousins), then we are five and they are a hundred.
But if there is a quarrel with an outsider then we are five plus a hundred।"