Why cant i see my message preview on the lockscreen samsung galaxy a5

[amartinez1234]

I have been trying to change my settings so that i can see the preview of my texts when my phone is locked, and so i dont have to unlock to see the text. Websites have told me to change the setting to "enabe message preview" or something like that, as a 3rd option, but on my phone it only shows 2/3 options and not the one im looking for. Please help.