This shows the weakness of god as the god need someone to save the earth. Is the god not powerful enough to save earth itself.
Weakness? No....actually wisdom.The sacrifice of Jesus fulfilled a need for divine justice. What is justice? From a human point of view it might mean an application of the rules of law. The book Right and ReasonEthics in Theory and Practice puts it this way... justice is connected with law, obligation, rights, and duties, and measures out its awards according to equality or merit. But, Gods view of justice, involves more than the application of regulations out of a sense of duty or obligation.
According to Psalm 37:28 Jehovah is a lover of justice. Therefore, He always does what is right and fair according to his own perfect standard. Jehovahs justice is perfectly balanced. He is never too lenient, never too harsh. He punishes unrepentant wrongdoers but extends tender mercy to repentant ones.
What was the need? It involved Adam. Being created perfect, Adam and Eve had produced no children before they sinned, so, no children were born perfect. All of Adams offspring were produced with a defect....sin, and sin leads to death. If God had just ignored this, he also would have ignored his own righteous standards. God could not do that and become guilty of being unrighteous. He did not sidestep the requirements of absolute justice. Because he didnt, no intelligent creature could ever legitimately find fault in this respect. Without ignoring the requirements for justice, how could a provision be made to deliver Adams offspring who would demonstrate loving obedience to Jehovah? If a perfect human was to die sacrificially, justice could allow for that perfect life to provide a covering for the sins of those who would in faith accept the provision. Since one mans sin (that of Adam) had been responsible for causing the entire human family to be sinners, the shed blood of another perfect human (Jesus), could balance the scales of justice. Now Adams offspring could be delivered. But, there was no such perfect human. So, Jehovah himself made the provision. In order to demonstrate justice, God sent his only-begotten Son who was willing to do his part. Humbly leaving behind his heavenly glory and becoming a perfect human, Jesus died on behalf of mankind.
(Romans 3:23-26) . . .For all have sinned and fall short of the glory of God, 24 and it is as a free gift that they are being declared righteous by his undeserved kindness through the release by the ransom [paid] by Christ Jesus. 25 God set him forth as an offering for propitiation through faith in his blood. This was in order to exhibit his own righteousness, because he was forgiving the sins that occurred in the past while God was exercising forbearance; 26 so as to exhibit his own righteousness in this present season, that he might be righteous even when declaring righteous the man that has faith in Jesus.