By faith Abel offered to God a more acceptable sacrifice than Cain, through which faith he was attested as righteous, God himself showing his approval by accepting his (autou | αὐτοῦ | gen sg masc3rd) gifts. And though he died, he still speaks through his (autēs | αὐτῆς | gen sg fem3rd) faith.
Reference
Hebrews 11:4
Sequence
3298