Genesis 38:11

At thy father’s house, whither he sent her from his house, that Shelah might not be insnared by her presence and conversation. So he dismissed her with a pretence of kindness, and a tacit promise of marriage to her, which he never intended to keep, as the following words imply; for he said; or rather, but he said; for the Hebrew chi oft signifies but, as Genesis 45:8; Psalms 37:20; Ecclesiastes 2:10; Ecclesiastes 6:2. So here is an opposition between what he said to Tamar, and what he said to himself, or in his own heart, as that word said is oft used: he intimated to her that he would give Shelah to her, but he meant otherwise, and said in himself, I will not do it,

lest peradventure he die also as his brethren did; imputing the death of his two sons either to her fault, or to her unluckiness, rather than to his own or his son’s miscarriages.