Humidity turns from vapor to frost as the water particles touch the ice cold glass. The slight scratches on the glass directs the formation of crystals.
Frost is damaging to some plants. Farmers make every effort to protect their corps or plant according to the tables that show them the from frost free dates. The water in the plants will expand breading the cells within the plant. This ruins the plant for market.
Just as frost damages plants so Christians need to guard their heart from turning cold. A cold heart is not receptive to the things of God. Without our being willing to receive from God we can't believe God's word and follow Him.
Psalm 78:47 "He destroyed their vines with hailstones And their sycamore trees with frost."
Lord let us not be cold towards You. Give us willing hearts that will respond to Your direction. Thank you. In Jesus name. Amen.