Romans 16:18

For such serve not the Lord Jesus Christ, but their own belly, and by good words and fair speeches, deceive the hearts of the simple.

James 1:8

A double-minded man is unstable in all his ways.

1 Thessalonians 2:5

For neither at any time used we flattering words, as ye know, nor a cloak of covetousness: God is witness:

Treasury of Scripture Knowledge

Summary

They speak vanity every one with his neighbour: with flattering lips and with a double heart do they speak.

General references

Bible References

Flattering

Romans 16:18
For such serve not the Lord Jesus Christ, but their own belly, and by good words and fair speeches, deceive the hearts of the simple.
1 Thessalonians 2:5
For neither at any time used we flattering words, as ye know, nor a cloak of covetousness: God is witness:

General references

Acts 12:22
And the people shouted, It is the voice of God, and not of a man.