Adam Clarke on 1 John 5:12

He that hath the Son hath life - As the eternal life is given In the Son of God, it follows that it cannot be enjoyed without him. No man can have it without having Christ; therefore he that hath the Son hath life, and he that hath not the Son hath not life. It is in vain to expect eternal glory, if we have not Christ in our heart. The indwelling Christ gives both a title to it, and a meetness for it. This is God's record. Let no man deceive himself here. An indwelling Christ and Glory; no indwelling Christ, No glory. God's record must stand.