He spoke on Thursday at Pine Trails Park, about two miles from the scene of the Valentine's Day tragedy.
Rizzo's hometown was once named the safest city in Florida.
"I come home to Parkland to what should be everybody's first concern, and that's showing our kids out there - the students at Stoneman Douglas and of Broward County and from all over the country - that we care about their lives and about their future," Rizzo said in front of thousands, still grieving from the tragedy. "I've been very impressed with talking to the students and how they're taking care of each other and how they're coming together. I'm so grateful to the teachers, the coaches, the administration and all the first responders that tried to protect them."
"I am only who I am because of this community. And I just want all of you to know how proud I am to be part of this community. I want you to know that you are not alone in your grief."
"We're all grieving with you. The entire country is grieving with you. So whatever comfort I can give, I will give. Whatever support I can offer to our students, teachers, coaches and families and first responders, you'll have it."
"I went to Stoneman Douglas. I grew up in Stoneman Douglas. I played on those fields. I went to those classes. I studied in those classrooms - the same school we saw on videos yesterday - for all the wrong reasons."
"We see this on TV too often. I feel like it's all the time. There's a cycle to it. We get horrified that this violence is inflicted on our kids. We get angry that there's nothing we can do and nothing is done about it. And then we ultimately get immune and move on to something else. But then it happens in our own town - in your own school, or the movie theater, or a nightclub, or a church. And we realize that it can happen to us, in our safe and tight knit community, Parkland."
"In fact there are a lot of communities out there that know exactly what we're going through right now and have to relive these moments again and again look I'm a baseball player but I'm also an American, I'm a Floridian, and I'm a Park Lander for life. Well I don't have all the answers I know that something has to change before this is visited on another community and another community."
"I will make one plea to all the teachers, coaches, parents and especially the students of Parkland - this just happened yesterday. And I promise you we are going to be mourning, grieving and a bit broken for awhile. We're human. Maybe a long while. But I promise the cameras are going to move on. The demands of everyday life will intrude again. Classes are going to start again. The seasons are going to change and the sun is going to rise and all we'll have left is each other. We don't know who's hiding in sadness, or feelings of guilt and loneliness, or who needs help and is too proud or afraid to ask. We have to be there for each other. We have to cope with our pain and we have to alleviate each other's pain."
"We have to be the best possible versions of ourselves. Teachers need to be there for the students in the most critical times right now. Parents and kids, you need to be there for your teachers because they love you so much and unconditionally and you'll never understand it, nor will i, nor will any of us. If I can stand up here and speak for love and kindness and compassion, then I think we should all be able to do that as one."
"Thank you all. God bless and I love you."