45 So, can Christians still sin

It's 1 John vs 1 John

The New Testament letter 1 John says:
That Christians cannot sin.

Uh, hold on!

1 John says, too:
That Christians can sin.

In 1 John, believers cannot sin

1 John 3:9 Those who have been born of God do not sin, because God's seed abides in them; they cannot sin, because they have been born of God.

But then again in 1 John, believers can sin

1 John 2:1 My dear children, I write this to you so that you will not sin. But if anybody does sin, we have one who speaks to the Father in our defense--Jesus Christ, the Righteous One.

1 John 5:16 If anyone sees his brother commit a sin that does not lead to death, he should pray and God will give him life.

Recap: Now believers can sin and now they can't. Thus 1 John vs 1 John.