It is without doubt that God showed considerable mercy toward Jacob. In the story, Jacob deceived his father Isaac in order to get his blessing. This led to Isaac blessing Jacob instead of his brother Esau. One would usually at this point expect God to be very angry with Jacob, as he wrongfully received his dying father’s blessing. However, the opposite is the case. In a dream, God promises Jacob that he will “give [him] and [his] descendants the land on which [he is] lying” (Gen. 28:13). Toward the end of his life, God shows his mercy toward Jacob again: he allows Jacob as an old man to reunite with his beloved son Joseph. Jacob is even able to meet and bless his two grandsons. Again, this demonstrates the mercy God is showing to Jacob.
With regard to David, one could argue that the mere fact that God allowed David to become king is a sign of God’s mercy. After all, David had simply been a humble shepherd. In addition to that, we can also see God’s mercy toward David in the fact that God protected David against King Saul, despite the fact that Saul had been an anointed king. Saul was chasing David, trying to kill him in order to protect his position as king. However, through God’s mercy, David always remained victorious. After Saul and his son fell in battle, David eventually became king himself—again a result of God’s mercy.
However, there is one clear occasion in David’s life where God was not merciful towards him at all: after David sent Uriah, Bathsheba’s husband, to war. David did this in order to be able to marry Bathsheba himself. This angered God very much, and instead of showing mercy, God ensured that David’s first son with Bathsheba died as a baby. However, God then showed David mercy again by providing him with another son: Solomon. All in all, David’s life was very successful and mostly filled with signs of God’s mercy.