There is nothing in the Bible that talks about church membership in the modern sense of taking classes, affirming the church’s doctrinal position, and signing a type of agreement, howevr in
Romans 12:4-5 ......
"For just as each of us has one body with many members, and these members do not all have the same function, 5so in Christ we, though many, form one body, and each member belongs
to all the others."
Hebrews 13:17,..........
“Obey your leaders and submit to them, for they keep watch over your souls as those who will give an account. Let them do this with joy and not with grief, for this would be unprofitable for you.”
1 Peter 5:1–3, .............
“Therefore, I exhort the elders among you, as your fellow elder and witness of the sufferings of Christ, and a partaker also of the glory that is to be revealed, 2 shepherd the flock of God among you, exercising oversight not under compulsion, but voluntarily, according to the will of God; and not for sordid gain, but with eagerness; 3 nor yet as lording it over those allotted to your charge, but proving to be examples to the flock.”
1 Timothy 5:17, ...........
“The elders who rule well are to be considered worthy of double honor, especially those who work hard at preaching and teaching.”