If there is anything we look for in human relationships, it is trustworthiness. We want to be able to depend on a friend's word; we want someone who will keep his promise.
God made extraordinary promises to Abram, later known as Abraham. He told him that his descendants would be very numerous and that, despite his old age, he would have a son from whom all these people would come. God was very pleased that Abraham took Him at His word, but He understood the human heart and the need we feel for a sign of trustworthiness.
We are the beneficiaries of the new covenant, not a promise of continued life through many descendants, but the pledge of everlasting life. God has given us a sign of this new covenant. God, so to speak, stands on one side and we on the other. Between us He has placed His Son upon the cross. This new covenant is sealed in the death of His Son. That death is the pledge of His everlasting love.
Today, there are many false prophets who promise happiness from money, power, prestige. But they can give no sign of their trustworthiness. God alone has given the ultimate sign of His fidelity, the death of His own Son upon the cross.
Lord, You are faithful to the end. Amen.