The important term Missio Dei (Mission of God) needs a biblical foundation. The sending of God by God is a foundational motive in the New Testament. Even at the very beginning of salvation history, shortly after creation, God became the first missionary. In Jesus, God is the missionary par excellence, and in the Holy Spirit, God is the most successful missionary. Mission is part of the nature of God, and therefore mission can only be described holistically and in a manner that transforms human mission into the image of God’s mission. In three chapters three important themes regarding the Missio Dei are discussed: 1. The recent history of the term in missiology; 2. the biblical and systematic foundations; 3. the debate between the Western and Eastern wings of Christianity over the filioque, that is the question, whether the Holy Spirit was sent by the Father alone or by the Father and by Jesus, His Son.