Phone is in safe mode

[enigma1]

I have 2 samsung phones a prevail and replenish they both are stuck in safe mode. This (safe mode) is clearly stated on the bottom left corner of both phonesCan someone please assist me in removing this. Thank you!
Note:
How does this happen that the phone goes in "safe mode"

[Nucleartx]

Samsung phones go into safe mode if after turning the device on, you continue to hold the power button. Just remove the battery, wait 15 minutes then put battery back in and turn on by holding the power button no more than 3 seconds.