I forget 4 digit pin

Do a hard reset.

First turn off your device.

And after turning off your device keep pressing Volume Up+Home Button+Power Button.

Release the power button when device is on but just keep pressing Volume Up and Home button until you are in recovery mode.

When you are in recovery mode already select Wipe Data Factory Reset by using the volume rocker to scroll down and power button to select now select factory reset and you should see a bunch of no's and only one yes scroll down to do yes and select it using the power button.