For some reason you may want to back up your chat message in whatsapp. Here are the steps invloved in restoring chat message of your whatsapp message. Steps involved are very simple and believed will help you .
Open WhatsApp and tap the three dots at the bottom-right.
Select settings > chat settings > backup. This will create a backup of your WhatsApp conversations.
If you accidentally deleted your chats, we suggest that you don't create a new backup. Instead, check the time of the previous backup, which can be found under the backup button mentioned in the previous step.
If this time is after you received the chats you deleted, uninstall and reinstall WhatsApp.
After verifying your phone number, WhatsApp will ask you if you want to restore a chat backup. Select yes.