The two sentences that most strongly foreshadow that wishing on the monkey's paw will bring about events that cause grief are:
B "He wanted to show that fate ruled people's lives, and that those who interfered with it did so to their sorrow." (paragraph 26)
D "If you must wish, he said gruffly, 'wish for something sensible." (paragraph 47)
These sentences suggest that tampering with fate or making unwise wishes could lead to negative consequences, hinting at the grief that will result from the wishes made on the monkey's paw.