than to hold fast to what you have until I come.
They are simply commanded to hold fast what they have until Christ comes.
This verse gives the remnant a clear mandate of persevering endurance.
18To the angel of the church in Thyatira write: 19I know your deeds — your love, your faith, your service, your perseverance — and your latest deeds are greater than your first. 20But I have this against you: You tolerate that woman Jezebel, who calls herself a prophetess. By her teaching she misleads My servants to be sexually immoral and to eat food sacrificed to idols. 21Even though I have given her time to repent of her immorality, she is unwilling. 22Behold, I will cast her onto a bed of sickness, and those who commit adultery with her will suffer great tribulation unless they repent of her deeds. 23Then I will strike her children dead, and all the churches will know that I am the One who searches minds and hearts, and I will repay each of you according to your deeds. 24But I say to the rest of you in Thyatira, who do not hold to her teaching and have not learned the so-called deep things of Satan: I will place no further burden upon you 25than to hold fast to what you have until I come. 26And to the one who overcomes and continues in My work until the end, I will give authority over the nations. 27He will rule them with an iron scepter and shatter them like pottery — just as I have received authority from My Father. 28And I will give him the morning star. 29He who has an ear, let him hear what the Spirit says to the churches.[’’]