The Old Testament teaching on 'life after death' is not clearly stated until later in the Book of Daniel (12:2) and 2 Maccabees (2 Mac. 7:9 ff). So the Sadducees, unlike the Pharisees did not accept this belief. So their question in today's Gospel reading was intended to trap Jesus. However Jesus' answer clearly stated that marriage is a matter that belongs to the present age whereas in the resurrected life, human relationships are raised to a totally new level as they refer to another age. So in this state, human beings are like angels and relationships are of brothers and sisters.
Morever, we know that our earthly covenantal relationship with God continues even after death. Hence, the declaration that "the God of Abraham, the God of Isaac and the God of Jacob" proves that there is life after death for Abraham and his descendants. By this Jesus shows the scriptural foundation for the faith that "the dead are raised" and they are alive in God (Lk. 20:37-38).
The defence of such a belief is clearly revealed in the martyrdom we see in 2 Maccabees by the seven brothers and their mother who professed their faith in the face of death. Such faith was possible as they knew that the love of God could comfort and strengthen them in everything good that they did and likewise protect them and guard them from the evil one.
Lord, may our hearts always turn towards Your love and the fortitude of Jesus Christ.