Psalm 119:64 (NIV)
64 The earth is filled with your love, Lord; teach me your decrees.

David pleads that God is good to all the creatures according to their necessities and capacities; as the heaven is full of God's glory, so the earth is full of his mercy, full of the instances of his pity and bounty. [Matthew Henry]

Samson, whom no earthly power could subdue during the twenty years that he was energized by the Spirit of God under his Nazarite vow, yet as soon as his locks were shorn was weak as another man. David, who, while he walked with God was the man after God's own heart, yet at length, when out of communion, could be guilty of the most appalling sins. We have no strength of our own to stand against temptation. The longest life, the most devoted service, is no security against a fall. I remember, when a young man, seeing, at a lecture on magnetism, a piece of soft iron brought on the platform and shown to be unable to hold up a needle. A coil of copper wire was then put round it, and connected with an unseen battery. Now it held, first nails, next chisels and other tools, till all the weights of the institution were brought, and it sustained them every one by the magnetic power. At a signal the wire was cut, and they all fell to the ground. It could no longer hold up the smallest thing. Its magnetic power was not in itself, but in its connection with the unseen battery.