“Give ear, O heavens, and I will speak, and let the earth hear the words of my mouth. May my teaching drop as the rain, my speech distill as the dew, like gentle rain upon the tender grass, and like showers upon the herb. For I will proclaim the name of the LORD; ascribe greatness to our God!” – Deuteronomy 32:1-3
God gave Moses this song (Deut 32:1-43), and instructed him to write it down and teach it to Israel (Deut 31:19). The song is not a happy ditty intended by God to bring joy to the hearts of the Israelites. God desired for the song to remind Israel how they turned from God, even though he upheld his part of the covenant and provided for Israel’s needs.
The song begins with a call for all the universe to testify to what God has to say. In spite of Israel not being the witness they were called to be, God will get his message to the nations. God will use the miracle of nature to convey his teachings if Israel refuses to remain loyal. The existence of God is proven to all of mankind through the natural world and every soul is responsible for responding to that unmistakable knowledge. Martin Luther said, “He calls to witness heaven and earth, that is, all creatures. And it also happens that when the godless are chastened, they think that all creatures are hostile to them. This is produced by the consciousness of sin, which is revealed through the Law. Thus every creature agrees with the Law as a witness of it.” Man sees evidence of a Creator around him and instinctively knows the truth of the moral law.
The rocks and trees tell a purer tale of God, then do we, his disciples. Though our poor evangelization must certainly frustrate God, he still uses us to pass his message of salvation to the nations. God’s elect, throughout the ages, have been instructed to bring the gospel and truth of salvation in the Lord to those who sense the reality of God around them. God’s adopted children are to proclaim his name and his teachings to the nations.
 Martin Luther, Luther’s Works, Vol. 9: Lectures on Deuteronomy, ed. Jaroslav Jan Pelikan, Hilton C. Oswald, and Helmut T. Lehmann, vol. 9 (Saint Louis: Concordia Publishing House, 1999), 290.