Therefore are ye come to your servant; not that he saith or thought that this was their design, but an effect of Divine Providence. The meaning is, Therefore hath God directed you this way, that I might have an occasion of performing my duty to you, which I cheerfully embrace.
Related Commentaries of Genesis 18:5
Genesis 18:5
5 And I will fetch a morsel of bread, and comfort ye your hearts; after that ye shall pass on: for therefore are ye come to your servant. And they said, So do, as thou hast said.