Albert Barnes Commentary Matthew 23:19

"Ye blind: for which is greater, the gift, or the altar that sanctifieth the gift?" — Matthew 23:19 (ASV)

The altar that sanctifieth the gift. The altar, dedicated to God, gave all the value or holiness to the offering, and must therefore be the greatest, or of the most importance. If, therefore, one is bound to the fulfillment of an oath, it must be the altar.