Commentary for Deuteronomy 30:19

העדתי בכם היום את השמים ואת הארץ I CALL AS WITNESSES AGAINST YOU THE HEAVEN AND THE EARTH, which exist for ever, and when evil will befall you they will be witnesses that I have warned you regarding all this (cf. Targum Jonathan on). Another explanation of העדתי בכם את השמים וגו׳ I CALL THE HEAVEN [AND THE EARTH] AS WITNESSES AGAINST YOU: The Holy One, blessed be He, said to Israel, “Look at the heavens which I have created to be at your service; have they perhaps ever changed their character? Has the orb of the sun perhaps ever failed to rise in the East and to give light to the whole world, just as is stated, (Ecclesiastes 1:4—5) “And the sun riseth, and the sun goeth down [and hasteth to its place where it arises]”?! Look at the earth which I have created to be at your service! Has it perhaps ever changed its character? Have you perhaps sown it and it did not bring forth, or have you sown wheat and it brought forth barley?! Now how is it with these that have been made neither with the end in view that they should receive a reward nor that they should suffer a loss — for if they act meritoriously (if they follow the natural laws by which they are governed) they receive no reward and if they were to fail they would receive no punishment? They have never changed their character! You, who if you act meritoriously do receive a reward and if you sin do receive punishment, how much the more so should you obey the commands of your Maker! (Sifrei Devarim 306:1).

ובחרת בחיים, you will opt for eternal life

העירותי בכם היום את השמים ואת האריץ, "I call as witness against you today both the heaven and the earth, etc." This whole verse appears superfluous in light of verse 15 where Moses asked the people to choose life rather than death. Why did he have to repeat it? Besides why did Mose change the sequence and choice here? In verse 15 the choice was between life and goodness on the one hand and death and evil on the other. Here the Israelites are given choices between life and death and blessing and curse. What did Moses mean when he rephrased what he said in verse 15? Besides, why did Moses not simply exhort the people to "choose life?"