從殷商甲骨卜辭與先秦文獻可證商周兩族是非常敬畏上天（上帝）的，不獨先民百姓信仰上帝，賢明的君王和聖人更是凡事開口必言天命，且又「以神道設教」訓戒百姓當謹守天命。《周易》的經與傳成書於信仰上帝的先秦時代，且皆為聖人之作，以「時代環境背景」和「作者身分品性」這兩條外證，可明其書思想必為信奉一位至高主「上天（上帝）」；其書所談論的真理也必圍繞著「天道」主旨。本文首先探討天帝在中國最早的本義，以甲骨文字為佐證；其次採「以史解易，以易證史」的方法，論證《周易》的核心思想、價值觀，與最高目標在於「天人合一」，並就順天應時細論天人合一的內容；最後得出天道為人事的法則之結論。

The oracle inscriptions of Shang Dynasty and documents of pre-qin dynasty show that the people in Shang and Zhou were all in awe of God. Not only did people believe in God, but also did the sagacious kings and saint who always claimed God's purpose for everything. People were also educated to obey God's will using religious explanation. The bible and bibliography of I-Ching were written by saints in the era of preqin when people believed in God. By using the external proof of the environment background and author identification, we c.[can find that the thoughts behind I-Ching is to worship only one almighty Lord (GOD); the truth discussed were all surrounded by God's thinking. This paper discusses the earliest definition of God in China by utilizing oracle scripts as proof; then it uses the methodology of explaining I-Ching by history and proving history by I-Ching to validate if the core thoughts, value, and ultimate goals of I-Ching is to unify God and human. Finally, we conclude that God's will is the rule of human via the discussions of unifying God and human by obeying God and nature operations.