Upvote:1
The cloud of witnesses mentioned in Heb. 12:1 is referring to the many faithful people mentioned in Heb. 11. The writer of Hebrews has just listed quite a few who lived before Christ and couldn't see the details of God's plan, but were still faithful.
"These all died in faith, not having received the things promised, but having seen them and greeted them from afar, and having acknowledged that they were strangers and exiles on the earth." (Heb. 11:13, ESV)
Some of these faithful examples endured very difficult circumstances (e.g. "They were stoned, they were sawn in two, they were killed with the sword...", Heb. 11:37, ESV). Because of their faith, the world was not worthy of them (Heb. 11:38).
All of these faithful examples are witnessing our Christian race as onlookers do at a track meet (Heb. 12:1-2). They cheer us on, saying, "You too can be faithful!" They don't speak to us directly, but the writings we have about their lives speak to us by way of encouragement.
I suggest reading Hebrews 11 straight through and then read Hebrews 12:1-2 and see if that makes any sense.