"Therefore, since we have so great a cloud of witnesses surrounding us, let us also lay aside every encumbrance and the sin which so easily entangles us, and let us run with endurance the race that is set before us"
The writer makes a distinction between "every encumbrance" that needs to be laid aside, and "the sin" that so easily entangles us. Both are obstacles, hinderances to running the race the Lord has set before us, yet one is characterized not as sin, but rather an impediment.
Those athletes running competitively in ancient times wore little or nothing during the race, minimizing any restriction to their movement clothing might impose. Their single-minded intensity in the athletic realm is held up as a challenge to us in the spiritual marathon that is our Christian walk. We, too, are to put off whatever the Holy Spirit reveals has become a drag upon our stride. A colorful leader I knew years ago phrased it: "I needed to get the junk out of my life!"
The "junk" we need to lay aside is often morally neutral in itself, and no spiritual hinderance for others, but has become an encumbrance in our heart and must be expunged. The temptation is always there to look around and question why we are not allowed to experience what others are free to enjoy, but Romans 14:12 must prevail--- "So then each one of us will give an account of himself to God." However innocuous my encumbrance may seem to someone else, however little need they may see for my getting it out of my life, however misunderstood I may be, the unchanging and unchangeable truth remains:
"Therefore we also have as our ambition, whether at home or absent, to be pleasing to Him. For we must all appear before the judgment seat of Christ, so that each one may be recompensed for his deeds in the body, according to what he has done, whether good or bad." (II Corinthians 5:9, 10)