In a similar way that land-based plants have roots, many aquatic plants have a holdfast. The purpose is to hold on to the solid substrate.
In verse 25, Jesus commands the church at Thyatira to holdfast to what they already have. What they have is the foundation of their faith. It is the Word of God. The good news of the gospel. It is the connection directly to the rock (Jesus).
As the waves of the times pull us this way or that, the hope is in the holdfast because it is what connects us to Jesus.
The way to keep the holdfast strong is to keep the plant strong and alive. The best way of doing that is through daily feeding, care and exercise. These are the things the church was commended for doing. Love. Faith. Service. Perseverance. Doing/Deeds. Obedience. Witnessing. Spreading the gospel.
I saw a kids teaching game along these lines. It is called the “deeds vs words” game. The kids are supposed to “Do what I say not what I do” (kind of like simon says, but with a twist). For example, sometimes I would do and say the same thing (say to touch your knees and I would touch my knees), but other times my words and actions wouldn’t match (I would say touch your head, but I would instead touch my shoulder). When about ½ the kids get out, points are rewarded to the rest and start over another round.
The point is that our actions not only keep our own “holdfast” healthy, but they, even more than our words, are our witness and what strengthens those around us. In the same way that the tallest and biggest trees grow only together in the forest (e.g., redwood forest), the stronger the holdfast of those around us the stronger is our own. In a community of plants, they overlap, grow together and weave into something even stronger than one plant could do on its own. In a community of believers, they keep us in faith and love, we serve together persevere together and witness together (to each other and to others).
Hold on to love faith service perseverance doing/deeds (truth/gospel). Do not hold to false teaching, Satan’s “so-called deep secrets”.
Hold only on to what you have until I come (love, faith, service, perseverence, doing/deeds)
obedience, faith, perseverance, service, love, to be witnesses and spread the gospel