The oath is omitted, its estimation being: By Allah, if the wolf eats him. The 'lam' is an emphasis for the oath. And His saying, 'Indeed, we would then be losers,' is a response to the oath, sufficient as a recompense for the condition. The 'wa' in 'And we are a group' is the conjunction of the state:

They swore to him that if what he feared from the wolf's attack was their brother among them - and their state is that they are ten men, with such as them matters become serious and calamities are sufficient - then they would certainly be a people who are losers, meaning doomed, weak, feeble, and incapable.

Or deserving to be destroyed because they have no benefit and no usefulness in their lives. Or deserving to be invoked against with loss and destruction, and it should be said: May Allah cause them to lose and destroy them when the wolf ate some of them while they were present.

And it was said: If we are unable to protect each other, then our livestock has perished if we lose it.

If you say: He excused them with two excuses, why did they respond to one of them and not the other? I say: It is that which angered them and caused them to taste the bitterest of matters.

They turned a deaf ear to him and paid no attention to him.