"loving obedience and hearty co-operation! Self-vindication is apparent in their response, “Wherein shall we return?” PK 707.1"
"Even from the days of your fathers ye are gone away from mine ordinances, and have not kept them. Return unto me, and I will return unto you, saith the Lord of hosts. But ye said, Wherein shall we return?"
The EGW passage directly quotes and references the question posed in Malachi 3:7, making it a clear allusion.
"The Lord reveals to His people one of their special sins. “Will a man rob God?” He asks. “Yet ye have robbed Me.” Still unconvicted of sin, the disobedient inquire, “Wherein have we robbed Thee?” PK 707.2"
"Will a man rob God? Yet ye have robbed me. But ye say, Wherein have we robbed thee? In tithes and offerings."
EGW directly quotes Malachi 3:8.
"Definite indeed is the Lord's answer: “In tithes and offerings. Ye are cursed with a curse: for ye have robbed Me, even this whole nation. Bring ye all the tithes into the store-house, that there may be meat in Mine house, and prove Me now herewith, saith the Lord of hosts, if I will not open you the windows of heaven, and pour you out a blessing, that there shall not be room enough to receive it. And I will rebuke the devourer for your sakes, and he shall not destroy the fruits of your ground; neither shall your vine cast her fruit before the time in the field, saith the Lord of hosts. And all nations shall call you blessed: for ye shall be a delightsome land, saith the Lord of hosts.” Verses 7-12 . PK 707.3"
"And I will rebuke the devourer for your sakes, and he shall not destroy the fruits of your ground; neither shall your vine cast her fruit before the time in the field, saith the Lord of hosts."
The EGW passage directly quotes Malachi 3:11.
"Will a man rob God? Yet ye have robbed me. But ye say, Wherein have we robbed thee? In tithes and offerings. Ye are cursed with a curse: for ye have robbed me, even this whole nation. Bring ye all the tithes into the storehouse, that there may be meat in mine house, and prove me now herewith, saith the Lord of hosts, if I will not open you the windows of heaven, and pour you out a blessing, that there shall not be room enough to receive it."
EGW directly quotes Malachi 3:8-10.
"God blesses the work of men's hands, that they may return to Him His portion. He gives them the sunshine and the rain; He causes vegetation to flourish; He gives health and ability to acquire means. Every blessing comes from His bountiful hand, and He desires men and women to show their gratitude by returning Him a portion in tithes and offerings—in thank offerings, in freewill offerings, in trespass offerings. They are to devote their means to His service, that His vineyard may not remain a barren waste. They are to study what the Lord would do were He in their place. They are to take all difficult matters to Him in prayer. They are to reveal an unselfish interest in the building up of His work in all parts of the world. PK 707.4"
"The Lord shall open unto thee his good treasure, the heaven to give the rain unto thy land in his season, and to bless all the work of thine hand: and thou shalt lend unto many nations, and thou shalt not borrow."
Both passages discuss God's blessings (rain, prosperity) and the expectation of a return or offering. The connection is thematic rather than a direct quote, but it's a clear parallel.