The writer of Hebrews is paraphrasing Habakkuk 2:3-4 in this passage. He’s stressing that our spiritual walk is made up of constant, focused, decisions to trust and obey the Lord…even when we can’t see change. He warns us against retreating or drawing back from trials simply out of fear. If you’re in the middle of a storm today, don’t allow fear to rule your life…don’t hesitate when apprehension rises in your throat…rather make a conscious decision to listen to that still small voice of the Holy Spirit and walk by faith.