All who see them will recognize that they are the offspring whom Hashem has blessed.

כל רואיהם יכירם כי זרע ברך ה' המה

This verse comes from Yeshayahu (Isaiah) 61:9. It reflects the idea that those who follow the ways of Hashem will be visibly recognized as blessed, and their descendants will carry that distinction. It conveys a sense of both spiritual and physical blessings being evident to all.