How to make Siri read text messages out loud from lock screen

Hello everyone

New member here! Just recently purchased an iPhone 6s and had a question about Siri. My previous phone (Nokia Lumia 1520 running Windows 8.1 with Cortana) would allow reading of incoming text messages/ calls out loud. Very use while during or working to respond. So my question is how do I allow Siri to do the same? Sorry if dumb question just cant seem to figure it out. Its a must or I will have to go return the iPhone.

Thanks for all the help!