Romans 16:18

For such persons are not serving Christ, our Master, but are slaves to their own appetites; and, by their smooth words and flattery, they deceive simple-minded people.

James 1:8

Vacillating as he is, irresolute at every turn.

1 Thessalonians 2:5

Never at any time, as you know, did we use the language of flattery, or make false professions in order to hide selfish aims. God will bear witness to that.

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 persons are not serving Christ, our Master, but are slaves to their own appetites; and, by their smooth words and flattery, they deceive simple-minded people.
1 Thessalonians 2:5
Never at any time, as you know, did we use the language of flattery, or make false professions in order to hide selfish aims. God will bear witness to that.

General references

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