How do we know what is good? The Bible tells us that God is good. In fact, it speaks of His goodness throughout Scripture.
“The Lord is good to those who wait for Him, to the soul who seeks Him. It is good that one should hope and wait quietly for the salvation of the Lord.” Lamentations 3:25-26.
It is amazing how God is blamed for all the horror we see around us, even among Christians who should know better. Even people who acknowledge a real personal devil believe this; furthermore, the devil himself is sometimes seen as the victim.
“And whoever receives one little child like this in My name receives Me. But whoever causes one of these little ones who believe in Me to sin, it would be better for him if a millstone were hung around his neck, and he were drowned in the depth of the sea.” Matthew 18:5-6.
“And we know that all things work together for good to those who love God, to those who are the called according to His purpose. For whom He foreknew, He also predestined to be conformed to the image of His Son, that He might be the firstborn among many brethren. Moreover whom He predestined [to be conformed to the image of His Son], these He also called; whom He called, these He also justified; and whom He justified, these He also glorified.” Romans 8:28-30.