Hebrews 3:18

3:18 And to whom did he swear they would never enter into his rest, except those who were disobedient?

Hebrews 6:13

6:13 Now when God made his promise to Abraham, since he could swear by no one greater, he swore by himself,

Hebrews 7:21

7:21 but Jesus ¹  did so ²  with a sworn affirmation by the one who said to him, “The Lord has sworn and will not change his mind, ‘You are a priest forever’” ³  –

[7:21]  ¹ tn Grk “he”; the referent (Jesus) has been specified in the translation for clarity.

[7:21]  ² tn The words “did so” are not in the Greek text, but are implied.

[7:21]  ³ sn A quotation from Ps 110:4 (see Heb 5:6, 6:20, and 7:17).