'Day' in the Bible

And do not grieve the Holy Spirit of God [but seek to please Him], by whom you were sealed and marked [branded as God’s own] for the day of redemption [the final deliverance from the consequences of sin].

For this reason He says,“Awake, sleeper,And arise from the dead,And Christ will shine [as dawn] upon you and give you light.”

Therefore, put on the complete armor of God, so that you will be able to [successfully] resist and stand your ground in the evil day [of danger], and having done everything [that the crisis demands], to stand firm [in your place, fully prepared, immovable, victorious].