[jiān chí bù xiè]
adhere to sth. unremittingly; hold on consistently and persistently; unremitting
make unremitting efforts
作坚持不懈的努力
Persevere and you'll succeed.
只要你坚持不懈， 你自会成功。
The broad working masses were undaunted, and persisted in their struggle with the result that the Qing government did not dare to conclude a new treaty with the imperialists.
广大劳动人民坚持不懈地进行斗争， 终于迫使清政府不敢公然和帝国主义续订新约。