8 I know thy works: behold, I have set before thee an open door, and no man can shut it: for thou hast a little strength, and hast kept my word, and hast not denied my name.
The very best open doors of opportunity are those open doors that have been set before us by God. While there are many doors of opportunity that lie open before us each and every day, we would do well to discern whether the door has been opened by the Lord. Consider Jael and Sisera. As Sisera fled from Barak, Jael invited Sisera into her tent and offered him milk and butter in a royal dish. And when he became weary and went fast asleep, she smote a nail into his temples. Although Jael offered Sisera safe entryway into her tent and was supposed to stand guard at the door to decieve would-be pursuers, ultimately, Jael proved to be the person that would take Sisera’s life. While Sisera was already in opposition to God, the principle taken from his entry into an open door remains the same: Unlike Jael, when the Lord promises you entry into a door, He will also ensure your safety while within.
[For when ye go over Jordan, and dwell in the land which the LORD your God giveth you to inherit, and when he giveth you rest from all your enemies round about, so that ye dwell in safety; Then there shall be a place which the LORD your God shall choose to cause his name to dwell there;] Deuteronomy 12:10-11