1 John 2:21

I have written to you, not because you are ignorant of the truth, but because you know it, and you know that nothing false comes from the truth.

2 Peter 1:12

For this reason I shall always persist in reminding you of these things, although you know them and are stedfast believers in truth which you already possess.

Romans 15:14-15

But as to you, brethren, I am convinced-- yes, I Paul am convinced--that, even apart from my teaching, you are already full of goodness of heart, and enriched with complete Christian knowledge, and are also competent to instruct one another.

Jude 1:5

I desire to remind you--although the whole matter is already familiar to you--that the Lord saved a people out of the land of Egypt, but afterwards destroyed those who had no faith.

Treasury of Scripture Knowledge

Summary

I have not written unto you because ye know not the truth, but because ye know it, and that no lie is of the truth.

Because ye know not

General references

Bible References

Because ye know not

Romans 15:14
But as to you, brethren, I am convinced-- yes, I Paul am convinced--that, even apart from my teaching, you are already full of goodness of heart, and enriched with complete Christian knowledge, and are also competent to instruct one another.
2 Peter 1:12
For this reason I shall always persist in reminding you of these things, although you know them and are stedfast believers in truth which you already possess.

General references

John 10:5
But a stranger they will by no means follow, but will run away from him, because they do not know the voice of strangers."