The Beatitudes are found in Matthew 5 and the Golden Rule follows in Matthew 7. The fifth Beatitude blesses the merciful who will also receive mercy. Matthew 25:40 contains a passage that bridges these two concepts when Jesus says, “Verily I say unto you, Inasmuch as ye have done it unto one of the least of these my brethren, ye have done it unto me.”
The Beatitudes contain simple statements with complex and multi-layered lessons. Each of the blessings result in a fulfillment which symbolizes salvation. The thirsty shall not thirst, the hungry shall not hunger and the mournful shall be comforted with eternal salvation.
The context of Matthew tells us that if we show mercy to our fellow man, we are showing mercy to Jesus. Jesus tells us in the Golden Rule to treat others — which Matthew 25 says is also Jesus — the way we want to be treated. Just as Jesus bore our sins on the cross, so too does he receive the goodwill that we bestow on others. Just as we are forgiven by his death and resurrection, we will receive the goodwill he grants in return for our own. Luke 6, which also tracks the Beatitudes, distills the concept down to this: “Give, and it shall be given unto you”
7 Blessed are the merciful, For they shall obtain mercy.