If you use on your new Samsung Galaxy S7 the messenger WhatsApp, then the content of new messages may be displayed directly on the lock screen. If you do not like that because persons can easily read your messages, you can hide those.
For this you must set the following setting in Android Marshmallow:
1. Open from the start screen the app menu and then the Android Settings.
2. Navigate here to "Lock screen and security" and then in the next submenu to "Notifications on lock screen"
3. Tap "Content on lock screen" and select then "Hide content"
Alternatively you can disable only WhatsApp notifications on the lock screen. Therefore you can search in the list below for WhatsApp and then turn off the switch for the notifications.
In this case, the notifications are disabled only for WhatsApp on the lock screen. You now know how to hide on the Samsung Galaxy S7 WhatsApp messages on the lock screen.