Genesis 42:31

And we said unto him, We are true men; we are no spies:

The words were addressed to Joseph in his position as ruler of the land, after he had spoken harshly to his brothers and taken them to be spies come to observe the country. In reply they denied being spies and insisted that they were honest, truthful men. That profession of honesty was tied to their stated purpose of having come with honest intent to obtain food, and with it they presented themselves as sons of one man from Canaan. Joseph treated their repeated claims to be truthful as statements that might be deceptive.

When they returned, the brothers repeated that same denial and profession of honesty to their father Jacob in reporting what had happened, together with their statement that they were twelve brothers. They also told him that the ruler had not believed them but had required them to leave one brother behind and to bring their youngest brother to Egypt, promising that on that condition the detained brother would be released and they would be free to trade.