That one cannot be sinfree is a doctrine of demons/devils.
Two false doctrines that are established by evil angels as the two major doctrines of spiritualism( miracles worked by evil angels or the miracle working power of demons) are: 1) The Immortality of the Soul doctrine which teaches consciousness in death. That man's soul lives on after he dies, either in heaven or hell burning, while the bible does not teach this but it teaches otherwise to this falsehood. 2) The teaching that Good is dependent on Evil and evil on Good, that the one needs the other to strive, thus making no difference between Good and evil, putting them as going together. This doctrine is established by the teaching that a man cannot live without sin and a man is saved in his sin; that a man could serve God who is good, while in sin (evil), thus the unity of Good and evil together. This doctrine makes no difference between the purest, noblest of the apostles of Christ and the most corrupt of the servants of Satan.
People who hold these teachings often point to the sinful life of the prophets and apostles who God redeemed from the vilest of sin making them sinfree, to justify their wicked evil ways to establish that dangerously false doctrine. These false doctrines open up the persons who hold those teachings to be a medium to evil angels or spiritualistic manifestations. Those who hold these teachings either come into contact with demons in the form of dead loved ones or just some dead person or some other form. They even appear to some as angels of light.
"...turn to Christ and be made sinfree and be free from being a child, a puppet of the devil"
This is why the doctrine of sinfreeness is important to counteract and destroy these false doctrines in the mind of mankind freeing them from the medium of demons. The doctrine of sinfreeness shows when God crucifies the old man through the truths of Christ that he is destroyed which is to say out of existence (Romans 6:1,2,6,7,11). It also shows that when the old man is dead he does not live on (2 Corinthians 5:14,15). Thus the doctrine of sinfreeness establishes that when a man is dead, his thoughts of the carnal mind perish (Romans 6:1,2,6,7). My dear people turn to Christ and be made sinfree and be free from being a child, a puppet of the devil. 1 John 3:8,9.