"This is the special work now before us. All our praying and abstinence from food will avail nothing unless we resolutely lay hold of this work. Sacred obligations are resting upon us. Our duty is plainly stated. The Lord has spoken to us by His prophet. The thoughts of the Lord and His ways are not what blind, selfish mortals believe they are or wish them to be. The Lord looks on the heart. If selfishness dwells there, He knows it. We may seek to conceal our true character from our brethren and sisters, but God knows. Nothing can be hid from Him. 2T 34.1"
"But the Lord said unto Samuel, Look not on his countenance, or on the height of his stature; because I have refused him: for the Lord seeth not as man seeth; for man looketh on the outward appearance, but the Lord looketh on the heart."
The EGW passage directly references the idea that God looks on the heart, which is the central point of 1 Samuel 16:7. The wording is not identical, but the concept is clearly drawn from this verse.
"The fast which God can accept is described. It is to deal thy bread to the hungry and to bring the poor which are cast out to thy house. Wait not for them to come to you. The labor rests not on them to hunt you up and entreat of you a home for themselves. You are to search for them and bring them to your house. You are to draw out your soul after them. You are with one hand to reach up and by faith take hold of the mighty arm which brings salvation, while with the other hand of love you reach the oppressed and relieve them. It is impossible for you to fasten upon the arm of God with one hand while the other is employed in ministering to your own pleasure. 2T 34.2"
"Is it not to deal thy bread to the hungry, and that thou bring the poor that are cast out to thy house? when thou seest the naked, that thou cover him; and that thou hide not thyself from thine own flesh?"
EGW directly quotes and expands upon Isaiah 58:7, making the connection undeniable.