In the scriptures, the number seven is associated with those things that are complete.  This association was established early on in the book of Genesis.  God created the heaven and the earth, finished the work in six days, and rested on the seventh day.  Natural creation was complete.  Since that time, there has been nothing else in nature created.  God established this pattern of seven days into a week.  The whole world observes a seven-day week based on God's pattern of creation. 

Numerous things in scripture are arranged in patterns of seven and each of them are complete.  Some things appearing in patterns of seven include seven women, seven pillars, seven eyes, seven horns, seven spirits, seven candlesticks, seven stars, seven cities of refuge, seven ewe lambs, seven headed dragon, seven headed beast, seven year release, seven years service, seven years of mourning for Israel, seven days of feast of unleavened bread, seven days of consecration, seven sprinklings of cleansing, seventh month of atonement.  Sevens are also associated with complete uncleanness, complete shame of sin, complete victory, complete punishment of sin. 

            The name "seventh" is associated with completion and with rest. 

We only took a small sampling of the use of the number seven and its association with completions in this study.  Hopefully, this will spur the reader on to further studies on this subject.