Dietrick Bonhoeffer says in his book "Life Together":
"God has willed that we should seek and find His living Word in the witness of a brother/sister, in the mouth of a man/ woman. Therefore, the Christian needs another Christian who speaks God's Word to him/her. He/she needs him again and again when he becomes uncertain and discouraged, for by himself he cannot help himself without belying their truth. He needs his brother man as a bearer and proclaimer of the divine word of salvation. He needs his brother solely because of Jesus Christ. The Christ in his own heart is weaker than the Christ in the word of his brother, his own heart is uncertain,, his brother's is sure."
Yes we are surrounded by a great cloud of witnesses so that we might run the race of life with faith in God and his promises. We look back to those who have gone before and we rely on those with us now for their faith to strengthen my faith as we follow Christ o our journey of faith.
From Tim Zingale's Sermon "Surrounded By a Great Cloud of Witnesses