Only God can cause the increase but I shall see how He leads me to share what I see as the truth in His words. Hebrews 3 at link below.
Bible Gateway passage: Hebrews 3 - King James Version
Hebrews 3:11 So I sware in my wrath, They shall not enter into my rest.) 12 Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God....
18 And to whom sware he that they should not enter into his rest, but to them that believed not? 19 So we see that they could not enter in because of unbelief.
I quoted the above reference form 3rd chapter as it leads into the 4th chapter at the link below; about how believing in Him is how we enter into that rest that we are saved.
Hebrews 4:1Let us therefore fear, lest, a promise being left us of entering into his rest, any of you should seem to come short of it. 2 For unto us was the gospel preached, as well as unto them: but the word preached did not profit them, not being mixed with faith in them that heard it. 3 For we which have believed do enter into rest, as he said, As I have sworn in my wrath, if they shall enter into my rest: although the works were finished from the foundation of the world.
9 There remaineth therefore a rest to the people of God. 10 For he that is entered into his rest, he also hath ceased from his own works, as God did from his. 11 Let us labour therefore to enter into that rest, lest any man fall after the same example of unbelief.
So if someone was running that race as His disciple to obtain salvation, then he is denying Him and that rest by working for his salvation.
The Galatians were doing that thinking they can resort to their own power in finishing what Christ as started in us with the Holy Ghost, but by the religious flesh.
Galatians 3:1O foolish Galatians, who hath bewitched you, that ye should not obey the truth, before whose eyes Jesus Christ hath been evidently set forth, crucified among you? 2 This only would I learn of you, Received ye the Spirit by the works of the law, or by the hearing of faith? 3 Are ye so foolish? having begun in the Spirit, are ye now made perfect by the flesh? 4 Have ye suffered so many things in vain? if it be yet in vain.
Granted this was attempted to be done by circumcision but even the commitment to follow Christ which is a man made bondage which is a promise declaring to God that he will finish it, even though God said He will do it all by the New Covenant and we were to believe Him to finish His work in us to His glory as we are the work of His hands.
Galatians 5:1Stand fast therefore in the liberty wherewith Christ hath made us free, and be not entangled again with the yoke of bondage. 2 Behold, I Paul say unto you, that if ye be circumcised, Christ shall profit you nothing. 3 For I testify again to every man that is circumcised, that he is a debtor to do the whole law. 4 Christ is become of no effect unto you, whosoever of you are justified by the law; ye are fallen from grace. 5 For we through the Spirit wait for the hope of righteousness by faith.
So if any believer does circumcision, which is the smallest letter of the law, then they are to do the whole law, then what do you think a promise to God is, but the biggest letter of the law? Numbers 30:2 Ecclesiastes 5:4-7 Which is why Jesus warned against it, even swearing to fulfill that oath by pointing out we cannot do God's work in us;
Matthew 5:33 Again, ye have heard that it hath been said by them of old time, Thou shalt not forswear thyself, but shalt perform unto the Lord thine oaths: 34 But I say unto you, Swear not at all; neither by heaven; for it is God's throne: 35 Nor by the earth; for it is his footstool: neither by Jerusalem; for it is the city of the great King. 36 Neither shalt thou swear by thy head,
because thou canst not make one hair white or black. 37 But let your communication be, Yea, yea; Nay, nay: for whatsoever is more than these cometh of evil.
Running that race is to be done as saved believers going onto perfection in walking in the light in fellowship with the Father & the Son as His disciples looking unto the author & finisher of our faith to help us lay aside every weight & sin daily in living that reconciled relationship with God thru Jesus Christ.