So...?

1 Samuel 23:3 KJV

And David's men said unto him, Behold, we be afraid here in Judah: how much more then if we come to Keilah against the armies of the Philistines?

A few things here:

First, though David's men had an enemy they still had a responsibility to aide those in need

Second, though they were afraid, they still must do the good thing

Third, though David's men questioned his decision David must still obey the voice of God and they must still follow him.

Fourth, though those who were helped were not of the same character as David, they still were to help them.

God gave sufficient warning to David that he and his men could escape. He provided for David's protection in a variety of ways in this chapter and the next but the key is that He did provide protection.