Some versions interpret this verse as referring to Sarah. "By faith Sarah, herself also barren, received ability to bear children even beyond the time of maturity, since she"
The abstract noun "faith" can be expressed with the verb "believe." Possible meanings are 1) it was by Sarah's faith. Alternate translation: "It was because Sarah believed God ... she" or 2) it was by Abraham's faith. Alternate translation: "It was because Abraham believed God ... he" (See: [[rc://en/ta/man/jit/figs-abstractnouns]])