Therefore, since we are surrounded by so great a cloud of witnesses, let us also lay aside every weight, and sin which clings so closely, and let us run with perseverance the race that is set before us, looking to Jesus the pioneer and perfecter of our faith, who for the joy that was set before him endured the cross, despising the shame, and is seated at the right hand of the throne of God.The Early Church Father Theodoret of Cyr says:
The models of godliness are set before us on all sides, he [the author of Hebrews] is saying, in such vast numbers as to resemble a cloud in density and and testify to the power of faith. Accordingly, let us keep our eyes on them, be light on our feet and rid ourselves of teh burden of unnecessary worries, in this way being able also to avoid sin that is easy to contract.Then comes this exquisite sentence:
Before everything else we need perseverance to succeed in the course ahead of us. He said sin "clings" because it is easily contracted and committed: the eye is fascinated, the ear charmed, touch titillated, tongue easily loosened and thought quickly directed to the worst.From Theodoret of Cyr, "Interpretation of Hebrews 12", as found in The Ancient Christian Commentary on Scripture, NT X: Hebrews (p. 209).
That about nails sin, doesn't it.