Remain in me, and I will remain in you. For a branch cannot produce fruit if it is severed from the vine, and you cannot be fruitful unless you remain in me. John 15:4 (NLT)
To remain in Jesus is to be convinced that He is more than enough, that what He did in saving us is a perfect work; we don’t have to add to it. It is to rest in His strength and allow His working in us to produce fruit.
It means we don’t strive in our own efforts to become or do what’s pleasing to God. Instead we focus our time and devotion on renewing our minds with the knowledge of who He is in us and who we are in Him. This is what empowers us to effortlessly live out our true identity in Him which is what being fruitful means.
Not abiding in Christ (John15:6) means seeking transformation outside Christ and what He did.
Remain in Christ as you get convinced of and rest in what He says in His Word concerning you and everything else. John 15:7.