In Romans 11:17-24 Paul uses the illustration of wild olives (Gentiles) being grafted in to a cultivated olive tree (the people of God). The natural branches are the Jewish people, yet some have been broken off because of their unbelief (Rom 11:20) and in their place Gentiles have been grafted in and will remain as long as they have faith.
Paul’s basic point is similar to that of Jesus in John 15:1-8 about the vine and the branches. Abiding in the vine produces fruitfulness in the branches. Fruitfulness in the branches is the evidence of connection to the vine.
In the natural process of gardening grafting can bring benefits both too the grafted plant and to the root plant. However both Paul & Jesus are focused on the benefits that the root/vine gives to the branches.
There are five main benefits that gardeners notice each of which can be applicable to believers grafted into Christ.
Protects against disease
The grafted in plant gains protection from the resilience of the root. ‘Lead us not into temptation but deliver us from evil.’ In Christ are we protected against the most damaging effects of sin.
Makes you stronger
As a result of drawing nourishment from the root, the grafted plan becomes stronger. ‘In Him we live and move and have our being’. We live by the Spirit, drawing strength from an endless well of supply.
As a result of a new root, the new graft produces fruit. This is often the main purpose of grafting. Jesus is clear those that bear no fruit will like the fig tree be cursed, those that bear bad fruit will be cut down, only those that bear good fruit will reap a reward. Fruitfulness is fundamental.
A damaged graft can be restored through connection to a healthy root. Sin damages us, scars us, hurts us. Our own sin and those who sin against us. Christ heals, restores, renews. Grace brings both forgiveness and the freedom to forgive others.
Through connection to a healthy root, future generations will bear a consistent likeness to the original root tree. If we are connected to Christ, those we disciple should end up not looking like us but looking like Christ. Christlikeness is evidence of connection to Christ.