How did God fulfill His promise?
God did it by uniting Himself with humankind in Jesus Christ. Jesus came into this world with the same spirit, or life, first Adam had before the sin in the Garden of Eden. The body of Jesus Christ was the same body the humankind had at the time of incarnation. The human body did not sin in the Garden of Eden. The human spirit sinned and subjected the body to decay. God educated Jesus, for about 30 years, and prepared Him for the day Jesus would make a correct decision on behalf of the new humankind God created in Jesus Christ.
Jesus, after His baptism, was led by the Holy Spirit into the desert to be tempted. Satan tempted Jesus in the same categories of sin he tempted the first human beings, the lust of eyes, the lust of the flesh, and the pride of life. These three categories are the root of all sins. Jesus, the Second, or last Adam faced the same temptation the first human beings did with one difference; the first Adam did not fast for 40 days. After Jesus fasted for 40 days, Satan approached Him and tried to turn Jesus’s eyes to self, instead of helpless humankind Jesus came to save. Luckily for us, Jesus was victorious.
By suffering and conquering temptation Jesus secured perfect and eternal life for all who would trust, have faith, in Him. Satan left Jesus in the desert “until an opportune time.” Many times during the three and one half years Satan tried to entice Jesus to turn His eyes on self, and the praises people were speaking about Jesus. However, Jesus, in the power of Spirit, never took His eyes off the mission to save the dying humanity. Because the spirit Jesus had at incarnation became perfect, the body of Jesus was sanctified, and it could not experience decay.
Jesus, for three and one-half years, traveled the countryside preaching the Good News and confirming it with numerous miracles. The Good News Jesus proclaimed was that day is very near when God would, in Jesus Christ, take away the sins of humankind into the eternal abyss; and restore the rebellious humankind to Himself as His children with full inheritance right in God’s domain. This event took place on the most significant and decisive day in all eternity.