Jesus says, “Blessed are the merciful, for they shall obtain mercy.” Mercy is perhaps God’s most defining characteristic. The Apostle Paul tells us: (Ephesians 2:4-5) “But God, who is rich in mercy, because of His great love with which He loved us, even when we were dead in trespasses, made us alive together with Christ (by grace you have been saved)”
That mercy is reciprocal is a common theme in the Sermon on the Mount. Jesus desires His followers to be merciful as He is merciful. (Matthew 6:14-15) "For if you forgive others for their transgressions, your heavenly Father will also forgive you. But if you do not forgive others, then your Father will not forgive your transgressions.” Also: (Matthew 7:1-2) "Judge not, that you be not judged. For with what judgment you judge, you will be judged; and with the measure you use, it will be measured back to you.”
Being willing to forgive and showing compassion for those in need are two ways where mercy can be extended. After concluding the parable of the Good Samaritan, Jesus asks, (Luke 10:36-37) "Which of these three do you think proved to be a neighbor to the man who fell into the robbers' hands?" And he said, "The one who showed mercy toward him." Then Jesus said to him, "Go and do the same."
The link between being merciful and happiness is clear. Being merciful in judgment and forgiveness lifts burdens of bitterness and anger leading to stress that no one can be happy (or healthy) while bearing. Mercy towards those in need results in unspeakable joy and happiness for the one showing mercy.
The fifth key to happiness: Be merciful and accept the mercy that God in His love has so willingly extended. (Matthew 11:28-30) "Come to Me, all who are weary and heavy-laden, and I will give you rest. Take My yoke upon you and learn from Me, for I am gentle and humble in heart, and YOU WILL FIND REST FOR YOUR SOULS. For My yoke is easy and My burden is light."