Do not let your conscience be hardened. It is like a body of water freezing in winter. It starts with a film of ice you can barely see. But once the film forms and the pond stays still, the glaze thickens. It starts thin, but quickly grows. It will first support small birds. It will then support a person walking over it. Eventually, you will be able to drive a loaded semi-truck over it. Conscience is like this. You may start with little things. But ignore your conscience and the Spirit and you will be willing to do worse and worse, falling farther and farther from God.
Adapted from Charles Haddon Spurgeon, Feathers for Arrows, (1870)