LXX Deut 31:21

καὶ ἀντικαταστήσεται ἡ ᾠδὴ αὕτη κατὰ πρόσωπον μαρτυροῦσα· οὐ γὰρ μὴ ἐπιλησθῇ ἀπὸ στόματος τοῦ σπέρματος αὐτῶν· ἐγὼ γὰρ οἶδα τὴν πονηρίαν αὐτῶν, ὅσα ποιοῦσιν ὦδε σήμερον πρὸ τοῦ εἰσαγαγεῖν με αὐτοὺς εἰς τὴν γῆν τὴν ἀγαθὴν ἣν ὤμοσα τοῖς πατράσιν αὐτῶν.

And when many troubles and afflictions have come upon them, this song will testify against them, because it will not be forgotten from the lips of their descendants. For I know their inclination, even before I bring them into the land that I swore to give them.”