Some people think that they don't need a Church to enjoy a personal relationship with Christ. However, can we deny that Christ started a church with Apostles and prophets, etc. for the "perfecting of the saints" (Eph 4:12)? During His mortal ministry, Jesus Christ authorized leaders in His church and sent them forth to "baptize all nations" and then regularly "break bread" and administer the Lord's Supper to His fold. Knowing this, can we suppose we can reach the "perfection" in Christ apart from Christ's Church even with its imperfect members and even imperfect leaders?
Elder Bednar makes the following analogy about the priesthood. The atonement of Christ is an umbrella that protects anyone who stands under it from the rain (sin, death). Priesthood is the staff that holds up the umbrella. A person holding the umbrella could hold that umbrella over others and shield others from the rain, but they themselves may not be necessarily standing under the protection of the umbrella.
Just because a man holds the umbrella (priesthood) and may be a unrepentant sinner, and may themselves not be under the protection of the atonement of Christ (umbrella), doesn't mean the umbrella isn't good, or the handle isn't good or that we shouldn't remain standing under it. The Doctrine and Covenants says "Amen to the priestood of that [wicked] man". Nevertheless, we all need to use the atonement of Christ and His church to keep out of the rain even if we see the holder of the umbrella getting soaked.