What is the meaning of Worden?

to become, to get, to grow, to turn

Used to form the imperfect tense of the passive voice, together with a past participle.

Ze worden gered. translates to “They are being saved.”

Ze werden gered. translates to “They were being saved.”

Consequently, Ze zijn gered. and Ze waren gered. would be translated as “They have been saved.” and “They had been saved.” respectively.

past participle of werden

first/third-person plural past indicative/subjunctive of werden

to speak (about)

past participle of weorþan

Source: wiktionary.org