For by it the elders obtained a good report.
For - Faith is all this; for, etc.
By - Greek, 'in this,' as their element.
The elders - not merely [hoi archaioi] the ancients, as though solely of the past; nay, they belong to one and the same blessed family as ourselves (Hebrews 11:39-40). "The elders" whom we all revere so highly for their faith and practice: a title of honour, as 'the fathers.' 'Paul shows how to seek in all its fullness, under the veil of history, the essential substance of the doctrine sometimes briefly indicated' (Bengel).
Obtained a good report - Greek, 'were testified of;' namely, favourably (cf. Hebrews 7:8): a phrase of Luke, Paul's companion. Not only men, but God, gave testimony to their faith (Hebrews 11:4-5; Hebrews 11:39). Thus they, having first received the witness of God, then being testified of themselves, have become "witnesses" to all others (Hebrews 12:1). The earlier elders had their patience exercised for a long life: those later, in sharper afflictions. Many things which they hoped for, and did not see, subsequently were conspicuously seen, the event confirming faith (Bengel).