Midrash for Taanit 3:11
ומנא לן דבתפלה דתניא (דברים יא, יג) לאהבה את ה' אלהיכם ולעבדו בכל לבבכם איזו היא עבודה שהיא בלב הוי אומר זו תפלה וכתיב בתריה (דברים יא, יד) ונתתי מטר ארצכם בעתו יורה ומלקוש
And, [as there] he taught: 'And on the Feast [the world] is judged through water,' therefore there he teaches: When do we [begin] to make mention of the Power of Rain. But let him teach: When do we [begin] to make mention of Rain: why, the Power of Rain? -R'Johanan said: Because Rain comes down by the Power [of God], as it is said, Who doeth great things und unsearchable, marvellous things without number.<span class="x" onmousemove="('comment',' Job V, 9-10. The Gemara cites IX, 10, but the commentators substitute for it V, 9 which makes the sequence of ideas clearer.');"><sup>13</sup></span>