In all of his 13 epistles in the New Testament, Paul begins with a salutation-a standard practice in his day. The writer and recipient are identified and a greeting is added.
Mercy means not receiving what you deserve, while grace means receiving what you don't deserve
In three of Paul's epistles, the salutation has noticeable differences. These are called the Pastoral Epistles-1 and 2 Timothy, and Titus. They are addressed to specific individuals and use warm terms of endearment: ″my true son in the faith″ (1 Timothy 1:2); ″my dear son″ (2 Timothy 1:2); ″my true son in our common faith″ (Titus 1:4). Except for Philemon, all the other Pauline epistles are addressed more generally to churches.
This more personal and intimate nature of the Pastoral Epistles is further distinguished by the greeting used in two of them. While all of Paul's epistles mention ″grace″ and ″peace″ in the salutation, the epistles to Timothy add the word ″mercy″.
Jews were used to greeting one another with ″shalom″ (peace). It was therefore unsurprising that Jesus greeted His disciples by saying, ″Peace be with you″ (John 20:19, 26). Christian practice continued this tradition. It also added the word ″grace″, which became an important concept in Christian doctrine (Romans 3:23-24; Ephesians 2:8). It therefore became common to have the words ″grace and peace″ in Christian greetings, as we see in Paul's epistles.
In 1 and 2 Timothy, Paul adds ″mercy″ in the salutation because he is mindful of the abundance of God's mercy (Ephesians 2:4) that was extended to him. He is deeply aware that God had forgiven him. Twice he testifies, ″I was shown mercy″ (1 Timothy 1:13,16).
Mercy means not receiving what you deserve, while grace means receiving what you don't deserve.
In forgiving us for our treachery against Him, receiving us as His prodigal children, and showering us with His love, God shows us both mercy and grace. The result is the all-rounded peace (within and in all relationships) that the word ″shalom″ conveys. We must think deeply about God's amazing grace and mercy, and drink constantly from them. Then the peace of God will replace our restlessness.