The Unchangeableness of God

"If God be unchangeable, then what we see- of Him at any moment, must be true of Him at every moment of time; true of Him also both before and after all the moments of time; always and for ever true of Him. If His purpose be to save mankind, that purpose stands firm for ever, unaffected by man's sin, unshaken by the fact of death, unaltered and unalterable by men, by angels, by naught conceivable." - Salv. Mundi.