Yes , basically, when someone remains in Christ and continues walking in the LIGHT...
Some disciples (many may be written ) in the NT, received Christ for a while, and followed Him, but later when His Words became too hard for them to bear, they left Him, and He let them go, so they did not either remain or did not become sons of God, unless later they returned to Him faithfully, in line with His Word and His requirements as written in His Word. Many people on this site/ forum/ have admitted they once were believers, and for one reason or another, or for no reason at all?! , they stopped being Christian. Others claim to be... and we must accept their claim, but not everything they say, post or do is in line with the Light....