And that thou mayst win to the sweetness of God's love, I set here three degrees of love, in the which thou be aye waxing. The first degree is called insuperable, the second inseparable, the third singular. Thy love is insuperable when nothing may overcome it, that is, neither weal nor woe nor anguish, lust of flesh nor liking of this world . . . Thy love is inseparable when all thy thoughts and wills are gathered together and fastened wholly in Jesus Christ, so that thou mayst no time forget him, buy aye thou thinkest on him . . . Thy love is singular when all thy delight is in Jesus Christ and in none other thing finds joy and comfort.
Richard Rolle: The Commandment.