"Had the antediluvians believed the warning, and repented of their evil deeds, the Lord would have turned aside His wrath, as he afterward did from Nineveh. But by their obstinate resistance to the reproofs of conscience and the warnings of God's prophet, that generation filled up the measure of their iniquity, and became ripe for destruction. PP 97.2"
"And God saw their works, that they turned from their evil way; and God repented of the evil, that he had said that he would do unto them; and he did it not."
Both passages illustrate God's willingness to withhold judgment when people repent. The Nineveh example is explicitly mentioned in the EGW passage.
The period of their probation was about to expire. Noah had faithfully followed the instructions which he had received from God. The ark was finished in every part as the Lord had directed, and was stored with food for man and beast. And now the servant of God made his last solemn appeal to the people. With an agony of desire that words cannot express, he entreated them to seek a refuge while it might be found. Again they rejected his words, and raised their voices in jest and scoffing. Suddenly a silence fell upon the mocking throng. Beasts of every description, the fiercest as well as the most gentle, were seen coming from mountain and forest and quietly making their way toward the ark. A noise as of a rushing wind was heard, and lo, birds were flocking from all directions, their numbers darkening the heavens, and in perfect order they passed to the ark. Animals obeyed the command of God, while men were disobedient. Guided by holy angels, they “went in two and two unto Noah into the …
"For as in the days that were before the flood they were eating and drinking, marrying and giving in marriage, until the day that Noe entered into the ark,"
Both passages describe the events leading up to the flood, specifically the people's indifference and the entry into the ark. The EGW passage elaborates on the details mentioned in Matthew.