Compare and contrast stateful versus stateless packet filtering

What will be an ideal response?

In stateless packet filtering the firewall examines every individual packet and decides whether to pass or block the packet, depending on that packet's contents. Stateless filtering does not filter on the basis of the context of the communication, and so it has limited value in a firewall.  Stateful packet filtering tracks information about a communication session, such as which ports are in use, drawing from the contents of multiple packets. It enables the firewall to build a more complete picture of a communication session in order to determine which traffic to allow through and which traffic to deny.