Commentaries:
God is showing through the church that all the prejudices against God and man can be dissolved and overcome through Christ. "New" here implies freshness, rather than from the point of time. It is part of the different perspective one receives upon conversion. Doing what He says to do is new for a convert because it means operating from the perspective of cooperation rather than competition. It is a new thing for a convert to show love, which is the exercising or the application of God's Word.
John W. Ritenbaugh
Reconciliation and the Day of Atonement
Other Forerunner Commentary entries containing John 13:34:
2 Timothy 3:1-2
1 John 4:7-8