16 Nor can We pass over in silence the profound impression of heartfelt gratitude made on Us by the good wishes of those who, though not belonging to the visible body of the Catholic Church, have given noble and sincere expression to their appreciation of all that unites them to Us in love for the Person of Christ or in belief in God. We wish to express Our gratitude to them all. We entrust them one and all to the protection and to the guidance of the Lord and We assure them solemnly that one thought only fills Our mind: to imitate the example of the Good Shepherd in order to bring true happiness to all men: "that they may have life, and may have it more abundantly" ( Saint John x. 10).
Source: Summi Pontificatus (Vatican.va)