By the Law or by the Spirit?

For the whole law is fulfilled in one word: “You shall love your neighbor as yourself.”
Galatians 5:14 ESV

But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, self-control; against such things there is no law.
Galatians 5:22-23 ESV

The book of Galatians is Paul's great discourse on grace over law and the Spirit over the flesh. We do not try to fulfill the legalistic letter of the law by the efforts of the flesh. But rather by the power of the Spirit we are enabled to fulfill the righteous heart of the law. 

Love is the fulfilment of the law and the first-fruit of the Spirit.