This verse of Matthew is similar to Luke, chapter 12:6-7, indicating a Q source. Jesus, via Matthew, compared human life to 2 sparrows. He asked whether 2 sparrows (οὐχὶ δύο στρουθία) that sold for a penny or a Greek “assarion” (ἀσσαρίου πωλεῖται), worth about 2 cents. were more valuable than humans. Not one of these sparrows would fall to the ground without the heavenly Father (καὶ ἓν ἐξ αὐτῶν οὐ πεσεῖται ἐπὶ τὴν γῆν ἄνευ τοῦ Πατρὸς ὑμῶν). God, the Father, could number all the hairs on their head (μῶν δὲ καὶ αἱ τρίχες τῆς κεφαλῆς πᾶσαι ἠριθμημέναι εἰσίν.). They should not be afraid (μὴ οὖν φοβεῖσθε), because they are more valuable that many sparrows (πολλῶν στρουθίων διαφέρετε ὑμεῖς). If God the Father cares for these insignificant birds, how much more is he concerned about humans. There was a continual theme about not being afraid.
Matthew has this unique presentation where Jesus has a solemn saying (ἐγὼ δὲ λέγω ὑμῖν) about ending all oaths, which would have been radical for his time. They were not to swear by anything at all (μὴ ὀμόσαι ὅλως). They should not swear by heaven (μήτε ἐν τῷ οὐρανῷ) since that is the throne of God (ὅτι θρόνος ἐστὶν τοῦ Θεοῦ). They should not swear by earth (μήτε ἐν τῇ γῇ) since that is the footstool for the feet of God (ὅτι ὑποπόδιόν ἐστιν τῶν ποδῶν αὐτοῦ). They should not swear by Jerusalem (μήτε εἰς Ἱεροσόλυμα) since that is the city of the great king (ὅτι πόλις ἐστὶν τοῦ μεγάλου Βασιλέως). They should not swear or take an oath by their own head (μήτε ἐν τῇ κεφαλῇ σου ὀμόσῃς) since they could not change one hair of their head to black or white (ὅτι οὐ δύνασαι μίαν τρίχα λευκὴν ποιῆσαι ἢ μέλαιναν). This was a blanket statement. There would be no more taking oaths, no more swearing by anything, anywhere.
Sirach then has a series of paradoxes. If you throw a stone straight up in the air, it will land on your head. A treacherous blow opens many wounds. If you dig a pit, you will fall into it. If you set a snare, you will be caught in it. Whenever you do evil, it will roll back on you. However, you will have no idea where it came from.