A.T. Robertson Commentary Romans 5:4

"and stedfastness, approvedness; and approvedness, hope:" — Romans 5:4 (ASV)

Knowing (ειδοτες). Second perfect participle of ειδον (οιδα), giving the reason for the previous exhortation to glory in tribulations. He gives a linked chain, one linking to the other (tribulation θλιψις, patience υπομονη, experience δοκιμη, hope ελπις) running into verse 5. On δοκιμη, see 2 Corinthians 2:9.