You must have seen various depiction of Lord Vishnu in pictures, movies and images. Somewhere, he is riding Gadura (the King of Birds); sometime, he is presented with 'Sankha-Chakra-Gada-Padma' and in many pictures, you have seen him, lying on a Serpent Bed that is known as 'Ananta-Sajya'.
Lord Vishnu is connected with this huge serpent with many heads in different incarnation. According to Hinduism, this huge serpent is known as Seshanaag and Lord Vishnu lies on it while taking rest.
There is certain significance of this depiction. Lord Vishnu has taken various avatars and he is the symbol of restoration of the world from the sea of sin. It is true that Gadura is regarded as the 'Vahana' (vehicle) of Lord Vishnu, but Seshanaag is equally co-related with Lord Vishnu, even in his every incarnation. Why he sleep on a serpent bed? Let's find out the answer-
1. Guide of Time
Lord Vishnu restores the world at the right time when the world has seen much of the sin. Seshanaag is the symbol of ‘Anant' means infinite. Lord Vishnu guides the time to be favorable on human kind. That's why he is seen lying on a serpent bed.
2. Expression of Lord Vishnu Himself
Lord Vishnu has several forms and shapes to save the world every time. According to Hindu religion, Seshanaag is believed as the form of Lord Vishnu's energy on which he lies to take rest.
3. Seat of All Planets
According to Hindu mythologies, it is also believed that Seshanaag holds all the planets inside its coil and sing chants of Lord Vishnu. If Lord Vishnu is signifies the Lord of the entire universe with all its planets and stars, this significance is really justified.
4. Protector of Lord Vishnu
Seshanaag not only provides resting place to the Lord, but it also protects him. Do you think it is ironical? At the birth of Lord Krishna, it was Seshanaag which protects baby Krishna from the turbulent storm while his father, Vasudeva was carrying him to Nanda's house. So, it is definitely the protector.
5. The Connection Is Never Ending
The bonding between Lord Vishnu and Seshanaag is eternal. In every incarnation, Seshnaag assisted Lord Vishnu to fight the evil in the world and restore it from the sin. In the Treta Yuga, Laksman was the incarnation of Seshanaag, while it took birth as Balaram in the Dwapar Yuga. And in both birth, they helped Ram and Krishna, respectively.
So, these are significance of Lord Vishnu, lying on Seshanaag. ‘Sesha' means ‘balance' and snake represents time. Lying on it means Lord Vishnu is the controller of time who is beyond everything.