Jesus told us he was sent only to the lost sheep of the House of Israel. Matthew 15:24. He also told us that his blood was to be shed for many for the remission of sins. Matthew 26:28.
If Jesus was only sent to the lost sheep of the House of Israel, then when his blood was shed, it was also obviously shed for the lost sheep of the House of Israel.
Why would Jesus' blood be shed for Israel? It could be that Creator had chosen Israel to be a light to the world. Since they had lived so wickedly and broken their covenant with God so that He told them they were no longer His people, the covenant now needed to be repaired if they were going to be a light to the world and fulfill their mission.
Jesus therefore came to repair and reinstate their covenant with God. His blood was shed for Israel, (The Ten Northern Tribes, not the Jews whose covenant was not broken,) to redeem them as a people.
According to the covenant, Israel had promised to follow the Law given through Moses. Then it stands to reason that those who would now be redeemed to the Lord by the blood of Jesus, are those who choose to follow the covenant vow of following the Law given through Moses. They accept the Torah, especially the spiritual aspect of the Torah as taught by Jesus.
Jesus taught that the greatest commandment is unconditional love. This is to love God with all our heart, soul, mind, and strength. We are also to love our neighbor as ourselves. He taught that when we do this, we have eternal life. Maybe the question here is, do we choose to believe Jesus, or today's religious doctrines? Luke 10:25-28.
Only someone who wants to continue living in darkness would try to change Jesus' teachings to say that there are other ways to gain eternal life. You will understand this because when someone choosing to live in darkness is confronted by the light, they get very angry.
Without unconditional love in our hearts, it is impossible to become one with our heavenly Father, who is unconditional love! Our light merges with His light and we become one. This is eternal life with our Lord.