From sharechair, one of my favorite tech blogs:

Thanks to my sweet daughter-in-law for bringing this tip to my attention. It’s a way to answer a text WITHOUT unlocking your phone. This could be very handy. In spite of fingerprint-recognition, I find myself tap tap tapping my lock code many times each day, usually just to answer a text message. This little hint […]
https://sharechair.wordpress.com/2016/02/23/how-to-answer-a-text-without-unlocking-your-iphone/