“Even as the Father has loved me, so have I loved you. Dwell (aorist imperative) in my love. If you keep (‘meditate on and obey' - aorist subjunctive) what I have commanded you will dwell continually in my love (future), even as I have kept (‘meditated on and obeyed') what He has commanded me (perfect), and dwell continually (present) in his love.”
Those who are His not only abide in Him, but also in His love. Those who reveal themselves as truly a part of the vine by their Christian fruitfulness will experience His continual love. Note that His love for those who are truly His own parallels the Father's love for Him. What greater love could there be than that? It is overflowing and permanent. Indeed it is established from the foundation of the world (Ephesians 1:4). And it is the love which passes knowledge (Ephesians 3:19). Thus their decision to abide in His love must also be permanent, something depicted by the aorist tense. It is a once for all dwelling. It is a decision that once made must be final. It is a permanent commitment resulting in a permanent position.
But we can only dwell in His love and remain there if we are obedient to what He commands us, and obedient to His word. Thus if we would dwell in His love we must ‘keep' His word, meditating on it and obeying it. The aorist subjunctive indicates the hope that they will permanently put themselves in a position whereby they keep what He has commanded them. Then they will abide in His love.
The use of the subjunctive, suggesting only possibility, indicates that Jesus still has Judas in mind (the disciples would at this stage certainly be including Judas as being part of the group to which the words were spoken even though he was absent). There was at least one who even now was not obeying His word. So while He is giving positive teaching to His disciples we can sense both the pressure He had sought to put on Judas, giving him a final opportunity to repent, and His awareness that He had failed to win him over. Humanly speaking the opportunity was still there, but in reality the opportunity had passed. And in future there would be other Judases, although not among the eleven.
‘Even as I have kept (‘meditated on and obeyed' - perfect tense - something which has happened in the past which continues to the present) what He has commanded me, and dwell continually (present) in his love.” He then cites Himself as their example. He Himself has demonstrated such a life and calls on them to follow in His steps. He has kept and is still keeping (perfect tense) what His Father has commanded Him, and continually dwells (present tense) in His love.
There is no compromise here. Permanent trust and obedience is required, a permanent dwelling in His love is promised. While the New Testament is aware of the weakness of many Christians it never condones it. Rather it encourages such weak Christians to recognise what God is doing in them and become strong, and it warns that the final test is perseverance lest any be deceived by a false profession. On the one hand it strongly confirms that those who are His will be confirmed to the end (1 Corinthians 1:8-9; Philippians 1:6; Jude 1:24 - note that all assume a work of God that is producing fruit), on the other it warns against complacency. All Christians can have assurance that they are in His love if they know that they are truly looking to Him only for salvation, none can have that assurance if they are deliberately continuing in long term disobedience and neglecting His word. You will never find anywhere in Scripture where it is taught that a fruitless so-called believer who is living in a state of neglect to God's word is given any assurance of salvation.