Deuteronomy 32:47

כי לא דבר רק הוא מכם FOR IT IS NOT A VAIN THING FOR YOU — it is not for nothing that you are to occupy yourselves laboriously with it. because much reward depends on it, כי הוא חייכם FOR IT IS YOUR LIFE (life is the reward). Another explanation: There is not one empty (ריק i.e., apparently superfluous) word in the Torah that, if you properly expound it, has not a grant of reward attached to it for doing so. You can know this, for so did our Rabbis say: It states (Genesis 36:22) “And Lotan’s sister was Timna”; (Genesis 36:32) “and Timna was concubine [to Eliphaz, Esau’s son]”. Why is this stated? Because she (Timna) said, “If I am unworthy to become his (Elphaz's) wife, would that I would become his concubine!”. And why all this (why does Scripture enter into all these details of her birth and marriage; of what interest is it to us)? To tell you in what distinction Abraham was held — that rulers and kings (Lotan was one of the chieftains of Seir, cf. Genesis 36:20—21) were eager to connect themselves by marriage to his descendants (Sifrei Devarim 336:1; cf. Rashi on Genesis 36:12).

כִּ֠י לֹא־דָבָ֨ר רֵ֥ק הוּא֙ מִכֶּ֔ם כִּי־ה֖וּא חַיֵּיכֶ֑ם וּבַדָּבָ֣ר הַזֶּ֗ה תַּאֲרִ֤יכוּ יָמִים֙ עַל־הָ֣אֲדָמָ֔ה אֲשֶׁ֨ר אַתֶּ֜ם עֹבְרִ֧ים אֶת־הַיַּרְדֵּ֛ן שָׁ֖מָּה לְרִשְׁתָּֽהּ׃ {פ}

For it is not a vain thing for you; because it is your life: and through this word you shall prolong your days in the land, into which you go over the Yarden to possess it.