"That these elements are in Healdsburg as well as in other places none will deny; and if Satan did not use them, he would use some other influence to the same end. But “woe to that man by whom the offense cometh;” for it were “better for him that a millstone were hanged about his neck, and he were cast into the sea.” God has His means of working. Men cannot always discern them, and by attaching so much importance to their own efforts they not only give the Lord no room to work, but are found working against Him. “Let him that thinketh he standeth take heed lest he fall.” “Ye therefore, beloved, seeing ye know these things before, beware lest ye also, being led away with the error of the wicked, fall from your own steadfastness. But grow in grace, and in the knowledge of our Lord and Saviour Jesus Christ.” 5T 483.1"
"But whoso shall offend one of these little ones which believe in me, it were better for him that a millstone were hanged about his neck, and that he were drowned in the depth of the sea."
The EGW passage directly quotes Matthew 18:6 regarding the consequences of causing offense, specifically the millstone imagery.
"Wherefore let him that thinketh he standeth take heed lest he fall."
The passage directly quotes the warning 'Let him that thinketh he standeth take heed lest he fall' from 1 Corinthians 10:12.