To conceive seed (εις καταβολην σπερματος). For deposit of seed. See Hebrews 4:3 for καταβολη.

Past age (παρα καιρον ηλικιας). Beyond (παρα with the accusative) the season of age.

Since she counted him faithful who had promised (επε πιστον ηγησατο τον επαγγειλαμενον). Sarah herself (αυτη--Σαρρα). Even Sarah, old as she was, believed God who had promised. Hence she received power.