A much overlooked aspect of Matthew's Gospel is the theme of heaven and earth. A close examination of Matthew reveals that this theme is woven regularly and skilfully throughout the First Gospel and interacts with several other theological emphases there. Rather than being a reverential circumlocution for God, "heaven" in Matthew is part of a highly-developed discourse of heaven language. Matthew has developed an idiolectic way of using heaven language that consists of four aspects: 1) an intentional distinction in meaning between the singular and plural forms of oupsilonrhoalphavoc; 2) the frequent use of the heaven and earth word pair as a theme; 3) regular reference to the Father in heaven/heavenly Father; and 4) the recurrent use of the uniquely Matthean expression, betaalphaolambdaalphatau, "kingdom of heaven." After providing a detailed examination of the historical precedents for each of these elements, this thesis argues that this four-fold idiolect serves one overriding theological purpose: to highlight the tension that currently exists between heaven and earth or God and humanity, while looking forward to its eschatological resolution. This emphasis on the current tension between heaven and earth functions for Matthew in a number of important theological, pastoral and polemical ways in his first-century context.