NET

27 the Jews established as binding on themselves, their descendants, and all who joined their company that they should observe these two days without fail, just as written and at the appropriate time on an annual basis.

Darby

27 the Jews ordained and took upon them, and upon their seed, and upon all such as joined themselves to them, so that it should not fail, that they would observe these two days according to their writing and according to their fixed time, every year;

KJV

27 The Jews ordained, and took upon them, and upon their seed, and upon all such as joined themselves unto them, so as it should not fail, that they would keep these two days according to their writing, and according to their [appointed] time every year;