"Those who labor for the good of others are working in union with the heavenly angels. They have their constant companionship, their unceasing ministry. Angels of light and power are ever near to protect, to comfort, to heal, to instruct, to inspire. The highest education, the truest culture, the most exalted service possible to human beings in this world, are theirs. GW 515.1"
"Are they not all ministering spirits, sent forth to minister for them who shall be heirs of salvation?"
The EGW passage directly reflects the principle that angels minister to those who will inherit salvation, as stated in Hebrews 1:14.
Often our merciful Father encourages His children and strengthens their faith by permitting them here to see evidence of the power of His grace upon the hearts and lives of those for whom they labor. “My thoughts are not your thoughts, neither are your ways My ways, saith the Lord. For as the heavens are higher than the earth, so are My ways higher than your ways, and My thoughts than your thoughts. For as the rain cometh down, and the snow from heaven, and returneth not thither, but watereth the earth, and maketh it bring forth and bud, that it may give seed to the sower, and bread to the eater: so shall My word be that goeth forth out of My mouth: it shall not return unto Me void, but it shall accomplish that which I please, and it shall prosper in the thing whereto I sent it. For ye shall go out with joy, and be led forth with peace: the mountains and the hills shall break forth before you into singing, and all the trees of the field shall clap their hands. Instead of the thorn shal…
"For my thoughts are not your thoughts, neither are your ways my ways, saith the Lord. For as the heavens are higher than the earth, so are my ways higher than your ways, and my thoughts than your thoughts."
The EGW passage directly quotes Isaiah 55:8-9.
"For my thoughts are not your thoughts, neither are your ways my ways, saith the Lord. For as the heavens are higher than the earth, so are my ways higher than your ways, and my thoughts than your thoughts. For as the rain cometh down, and the snow from heaven, and returneth not thither, but watereth the earth, and maketh it bring forth and bud, that it may give seed to the sower, and bread to the eater: So shall my word be that goeth forth out of my mouth: it shall not return unto me void, but it shall accomplish that which I please, and it shall prosper in the thing whereto I sent it. For ye shall go out with joy, and be led forth with peace: the mountains and the hills shall break forth before you into singing, and all the trees of the field shall clap their hands. Instead of the thorn shall come up the fir tree, and instead of the brier shall come up the myrtle tree: and it shall be to the Lord for a name, for an everlasting sign that shall not be cut off."
Ellen White directly references Isaiah 55:8-13 in this passage.