The quality of mercy is not strained. Mercy is something that has to be freely given; no one can force someone else to be merciful.

         Mercy is a very rare moral value. All the great spiritual masters have emphasized the importance of practicing mercy while dealing with others, especially those who are our opponents, enemies, and adversaries. Jesus Christ’s words in this regard are quite relevant. He said: “Blessed are the merciful, for they shall obtain mercy.” The spiritual connotation of his words is quite deep. He calls the merciful ‘Blessed’. Besides being blessed, which means being lucky, mercy shown to others wins hearts; it smoothes all the folds and creases of hurts, pains, and aches. According to Jesus’ words if we want to have God’s mercy for are misdeeds, we should simply practice mercy by forgiving others silently for the hurts and pain they might have given us. Mercy given, comes back to us in double measure. 

The quality of mercy is not strained.

It droppeth as the gentle rain from heaven
Upon the place beneath. It is twice blest:
It blesseth him that gives, and him that takes.
'Tis mightiest in the mightiest. It becomes
The throned monarch better than his crown.
His sceptre shows the force of temporal power,
The attribute to awe and majesty,
Wherein doth sit the dread and fear of kings;
But mercy is above this sceptred sway.
It is enthroned in the hearts of kings;
It is an attribute of God himself.
And earthly power doth then show likest God's
When mercy seasons justice. Therefore, Jew,
Though justice be thy plea, consider this:
That in the course of justice none of us
Should see salvation. We do pray for mercy,
And that same prayer doth teach us all to render
The deeds of mercy. I have spoke thus much 
To mitigate the justice of thy plea,
Which if thou follow, this strict court of Venice
Must needs give sentence 'gainst the merchant there.