Genesis 26:9

And Abimelech called Isaac, and said, Behold, of a surety [obviously] she [is] thy wife: and how saidst thou, She [is] my sister? And Isaac said unto him, Because I said, Lest I die [on account of] for her.

Geneva Bible - Then Abimelech called Isaac, and said, Lo, she is of a surety thy wife, and why
saidst thou, She is my sister? To whom Isaac answered, Because I thought this, It
may be that I shall die for her.

Genesis 20:5

Said he not unto me, She [is] my sister? and she, even she herself said, He [is] my brother: in the integrity [innocence] of my heart and innocency of my hands have I done this.

(Geneva Bible) - Said not he unto me, She is my sister? Yea, and she herself said, He is my brother; with an upright (e) mind, and (f) innocent hands have I done this.
(e) As one falling by ignorance, and not doing evil of purpose.
(f) Not thinking to do any man harm

Genesis 12:13

Say, I pray thee, thou [art] my sister: that it may be well with me for thy sake; and my soul shall live because of thee.