LXX Deut 17:20

ἵνα μὴ ὑψωθῇ ἡ καρδία αὐτοῦ ἀπὸ τῶν ἀδελφῶν αὐτοῦ, ἵνα μὴ παραβῇ ἀπὸ τῶν ἐντολῶν δεξιὰ ἢ ἀριστερά, ὅπως ἂν μακροχρονίσῃ ἐπὶ τῆς ἀρχῆς αὐτοῦ αὐτὸς καὶ οἱ υἱοὶ αὐτοῦ ἐν τοῖς υἱοῖς Ἰσραήλ.

Then his heart will not be exalted above his countrymen, and he will not turn aside from the commandment, to the right or to the left, in order that he and his sons may reign many years over his kingdom in Israel.