Your question: Using the bible, can you show proof of the date 1914?
My answer: Using the bible, you can crush the date 1914.
It is a sin and misstake to try to calculate the timepoint of God's Kingdom's establishment, as well as to predict the time point of the battle of Armageddon.
The apostles asked Jesus: "Lord, are you restoring the kingdom to Israel at this time?" 7 He said to them: "It does not belong to you to get knowledge of times and seasons which the Father has placed in his own jurisdiction; -Acts 1:6,7
Apostle Paul reaffirmed the principle in 1 Thessalonians 5:1: Now as for times and seasons, brothers, you need nothing to be written to you.
But a witness would point to the coincidence of the First World War in 1914. But the simple coincidence in calculating the year 1914 is a result of their disobedience. Satan then lead the nations to go to war that year, in order to make the Watchtower society believe that they did not sin in guessing about times ad seasons. Watchtower-society had just got rid of many false teachings and understood the Bible surely in the best way compared to other societies. So of course Satan had to try to deceive them in some way. And it has worked until now.