John Wesley on Isaiah 55:1

Thirsteth - For the grace of God and the blessings of the gospel. This thirst implies a vehement, and active, and restless desire after it. No money - Those who are most worthless and wicked, if they do but thirst may be welcome. Buy - Procure or receive that which is freely offered. Wine and milk - All gospel - blessings; in particular, that peace and joy in the Holy Ghost, which are better than wine, and that love of God which nourishes the soul, as milk does the body.