Romans 16:18

For men of that stamp are not bondservants of Christ our Lord, but are slaves to their own appetites; and by their plausible words and their flattery they utterly deceive the minds of the simple.

James 1:8

such a one is a man of two minds, undecided in every step he takes.

1 Thessalonians 2:5

For, as you are well aware, we have never used the language of flattery nor have we found pretexts for enriching ourselves--God is our 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 men of that stamp are not bondservants of Christ our Lord, but are slaves to their own appetites; and by their plausible words and their flattery they utterly deceive the minds of the simple.
1 Thessalonians 2:5
For, as you are well aware, we have never used the language of flattery nor have we found pretexts for enriching ourselves--God is our witness;

General references

Acts 12:22
and the assembled people kept shouting, "It is the voice of a god, and not of a man!"