/* Newer posts */
nav.blog-list-pagination .prev-label {
    visibility: hidden;
}
nav.blog-list-pagination .prev-label:before {
    visibility: visible;
    content: "New prev text";
}
/* Older posts */
nav.blog-list-pagination .next-label {
    visibility: hidden;
}
nav.blog-list-pagination .next-label:after {
    visibility: visible;
    content: "new next text";
}