Joy Doubled in the Joy of Another

I've been slowly reading through Desiring God by John Piper and this is a quote from the end of the chapter on love.

"Love is the overflow of joy in God that meets the needs of others. The overflow is experienced consciously as the pursuit of our joy in the joy of another. We double our delight in God as we expand it in the lives of others. If our ultimate goal were anything less than joy in God, we would be idolaters and no eternal help to anyone.Therefore, the pursuit of pleasure is an essential motive for every good deed. And if you aim to abandon the pursuit of full and lasting pleasure, you cannot love people or please God."