display both published and updated date

i want to display both updated and originally published date to humans on all posts and pages. i checked the forum and did add some codes, but nothing worked. currently, i am showing only updated date to humans. i would prefer to show first the modified or updated date and then the originally published date.

i am using the following css code.

.posted-on .updated {
display: inline-block;
}

.posted-on .updated:before {
content: "Updated: ";
}