"Those who do little for the Saviour in the salvation of souls and in keeping themselves right before God, will gain but little spiritual muscle. We need continually to use the strength we have that it may develop and increase. As disease is the result of the violation of natural laws, so is spiritual declension the result of a continued transgression of the law of God. And yet the very transgressors may profess to keep all of God's commandments. 4T 75.2"
"But strong meat belongeth to them that are of full age, even those who by reason of use have their senses exercised to discern both good and evil."
Both passages discuss the importance of consistent spiritual exercise and growth. EGW speaks of gaining 'spiritual muscle' through active service and obedience, while Hebrews 5:14 describes those who 'by reason of use have their senses exercised.' The lack of spiritual activity leads to declension.
"when the invalid is compelled to remain long inactive. It is use that gives power. 4T 75.3"
"If thou faint in the day of adversity, thy strength is small."
The connection is weak, but the idea of 'use that gives power' in EGW and 'strength is small' when one faints in Proverbs 24:10 share a general theme of activity and strength. However, the link is not strong enough to be a clear thematic parallel.
Nothing will give greater spiritual strength and a greater increase of earnestness and depth of feeling than visiting and ministering to the sick and the desponding, helping them to see the light and to fasten their faith upon Jesus. There are disagreeable duties that somebody must do or souls will be left to perish. Christians will find a blessing in doing these duties, however unpleasant they may be. Christ took the disagreeable task upon Himself of coming from the abode of purity and unsurpassed glory, to dwell, a man among men, in a world seared and blackened by crime, violence, and iniquity. He did this to save souls; and shall the objects of such amazing love and unparalleled condescension excuse their lives of selfish ease? shall they choose their own pleasure, follow their own inclinations, and leave souls to perish in darkness because they will meet with disappointment and rebuffs if they labor to save them? Christ paid an infinite price for man's redemption, and shall he say:…
"And the King shall answer and say unto them, Verily I say unto you, Inasmuch as ye have done it unto one of the least of these my brethren, ye have done it unto me."
Both passages emphasize the importance of serving others, particularly the needy and suffering. EGW highlights Christ's example of selfless service and challenges believers to follow suit, while Matthew 25:40 states that serving 'the least of these' is equivalent to serving Christ himself. The connection is strong and relevant.