Scripture gives the answer. A question for you, which 'body' is John referring to here?
1 John 2 My little children, I am writing these things to you so that you may not sin. But if anyone does sin, we have an advocate with the Father, Jesus Christ the righteous, 2 and he is the atoning sacrifice for our sins, and not for ours only but also for the sins of the whole world.
3 Now by this we know that we have come to know him, if we obey his commandments. 4 Whoever says, “I have come to know him,” but does not obey his commandments is a liar, and in such a person the truth does not exist; 5 but whoever obeys his word, truly in this person the love of God has reached perfection. By this we know that we are in him: 6 whoever says, “I abide in him,” ought to walk in the same way as he walked.