John Gill Commentary Genesis 14:23

"that I will not take a thread nor a shoe-latchet nor aught that is thine, lest thou shouldest say, I have made Abram rich:" — Genesis 14:23 (ASV)

That I will not [take] from a thread even to a shoelatchet ,
&c.] That is, from a thread used in sewing garments to, a shoelatchet, or the string which fastens the shoes to the foot, the least belonging to that; or from the hair lace of the head, to the shoelatchet of the foot; that is, he would take nothing of his from head to foot: the meaning is, that he would not take that which was of the least value and importance that could be conceived of, and which is more clearly expressed by what follows:

and that I will not take anything that [is] yours ;
the least thing that belonged to him, or to any of his subjects, for this reason:

lest you should say, I have made Abram rich ;
lest he should upbraid him with it afterwards, and say, that all his riches were owing to him; whereas God had promised to bless him, and make him rich and great, as he had begun to do, and still would more and more; and in whom his trusted, and to whom he was desirous all the glory of his greatness and riches should be ascribed.