Some Key Words

I think we've seen all of these by now.

Paraphrase

20 Claiming to love God and being unable to love each other makes our claim a lie, 21 for God has commanded us to love one another and the one who loves Him would obey Him willingly. 5:1 The believer is born of God, and therefor loves those whom He has claimed as His children.

Key Verse

4:21 - This sums it up: He has commanded us to love. If our love is for Him, His commandment should be cause enough for us to love others.

Thematic Relevance:	Professed love will show itself in works if it be real. That love we claim to have for God - finding our joy in Him - must include doing His will joyfully, which will is that we love others as He has loved us.
Doctrinal Relevance:	21 God's commandment is to love each other. 5:1 Jesus is Messiah, born physically of God the Father.
Moral Relevance:	We cannot help but love those God loves if we love Him. Why then do we allow them to get on our nerves so easily? Do we get on God's nerves so easily? This is a love that requires effort on our part. It's impossible without God's help, but it will even then remain impossible if we don't accept that help.

Some Parallel Verses

4:20

1Pet 1:8 - even though we haven't seen God, we love Him.

4:21

Lev 19:18 - the commandment delivered: love your neighbor as yourself - not just your brothers in Christ, but everybody. Mt 5:43-48 - in fact, the worse they are toward you, the more you ought to pray for them. Mt 22:37-40 - the commandment to love is the basis of all God requires. Jn 13:14 - we should be following the example of our teacher: Jesus. Jn 13:34 - who has commanded us as His Father commanded - to love each other.

5:1

Jn 1:3 - Jesus Christ created all things. Jn 3:3 - we must be born again - of God. Jn 8:42 - in which case we would love Jesus - who came from and is God.

New Thoughts

The same deep-seated need for improvement keeps coming through loud and clear. God, I've never loved in the terms You ask for. I barely know how. But You have promised to instruct and empower me to fulfill this main command. God help me to love. To love truly, as You loved. Loving strongly enough to give up my most precious possession to love another. Loving strongly enough not to count the consequences and be deterred. God I am weak. But Your grace is sufficient. Show Your power in my weakness, oh Lord. Demonstrate Your love in me.