'In that Day' in the Bible

Every man's work will be made clear in that day, because it will be tested by fire; and the fire itself will make clear the quality of every man's work.

Now I have applied these things, brothers, to myself and to Apollos as an illustration for your benefit, so that you might learn to "follow the written message." [Note: This is thought to have been a common way of referring, in that day, to the importance of adhering to Old Testament Scripture]. So, none of you should be more proud of one [leader] than of another.

Was any man already circumcised when he was called [by God to be a Christian]? Then he should not [try to] become uncircumcised. [Note: Some Jews in that day resorted to a surgical procedure in an attempt to conceal their circumcision]. Was any man uncircumcised when he was called? Then he should not become circumcised.

Now these events happened to those people as examples [to us], and they were written as warnings to us, to whom the fulfillment of the ages has come. [Note: This refers to past ages concluding with the coming of Christ in that day].