In Matthew 23:18, the King James Version (KJV) of the Bible quotes Jesus as saying, "And, Whosoever shall swear by the altar, it is nothing; but whosoever sweareth by the gift that is upon it, he is guilty."

This verse is part of a larger passage in which Jesus is delivering a series of rebukes and warnings to the scribes and Pharisees. Throughout this passage, Jesus is addressing the hypocrisy and spiritual blindness of the religious leaders of his time. He condemns them for their outward show of piety while neglecting the more important matters of justice, mercy, and faithfulness. In this particular verse, Jesus is criticizing their misuse of oaths and vows.

The context of this verse is important for understanding its meaning. In the preceding verses, Jesus denounces the scribes and Pharisees, calling them hypocrites and likening them to whitewashed tombs. He accuses them of being more concerned with outward appearances and their own self-righteousness than with seeking God and living in accordance with his will.

Into this context, Jesus inserts the words of Matthew 23:16-22. This passage addresses the scribes and Pharisees' misuse of oaths and vows, pointing out their inconsistencies and evasions in making oaths. Jesus is essentially saying that they are meticulous in making oaths about external, material things (such as the altar or the gift on the altar), while neglecting the deeper, spiritual significance of their words and commitments.

In this verse, Jesus is teaching about the importance of sincerity and truthfulness in our words and commitments. He is contrasting the value of swearing by the altar with swearing by the gift on the altar. In the Jewish tradition, the altar was a sacred and important symbol of worship and sacrifice. By swearing by the altar, one was invoking the name of God and affirming the truth of their words by the holiness of the altar. However, by swearing by the gift that is upon the altar, one was attempting to deceive and mislead by focusing on the lesser, material object rather than the sacredness of the altar itself.

In this way, Jesus is challenging the religious leaders to be authentic and truthful in their words and actions. He is calling them to a higher standard of integrity and righteousness, emphasizing the importance of genuine faith and obedience to God's will over empty religious practices and superficial displays of piety.

The themes present in this verse include the importance of sincerity, truthfulness, and integrity in our words and actions. Jesus is highlighting the value of genuine faith and devotion to God, as opposed to outward shows of religious observance. He is also condemning hypocrisy and legalism, urging his listeners to seek a deeper, more authentic relationship with God.

Symbolically, the altar and the gift represent the spiritual and material aspects of our lives. By swearing by the altar, we are acknowledging the sacredness and significance of our spiritual commitments. By swearing by the gift, we are focusing on the temporary and transient aspects of our lives. Jesus is teaching that our words and commitments should be grounded in a deep and genuine reverence for God and his will, rather than being superficial or self-serving.

In conclusion, Matthew 23:18 is a powerful reminder of the importance of sincerity and truthfulness in our words and actions. It serves as a warning against hypocrisy and legalism, urging us to seek an authentic and genuine relationship with God. This verse challenges us to be mindful of the deeper, spiritual significance of our commitments and to prioritize the values of faith, integrity, and righteousness in our lives.