John Calvin Commentary Mark 5:36

"But Jesus, not heeding the word spoken, saith unto the ruler of the synagogue, Fear not, only believe." — Mark 5:36 (ASV)

Fear not, only believe. The message about her death had induced despair, because he had asked nothing from Christ but relief for the diseased young woman. Christ therefore instructs him to be careful that he does not, by fear or distrust, shut out that grace, to which death will be no hindrance. By this expression, only believe, He means that He will not lack power, provided Jairus allows Him; and, at the same time, exhorts him to enlarge his heart with confidence, because there is no room to fear that his faith will be more extensive than the boundless power of God.

And truly, this is the case with all of us, for God would be much more generous in His blessings to us, if we were not so constricted; but our own meager desires hinder Him from pouring out His gifts on us in greater abundance.⁵²⁸ In general, this passage teaches us that we cannot go too far in believing, because our faith, however large, will never embrace even a hundredth part of the divine goodness.

⁵²⁸ “Mais la petitesse, et (par maniere de dire) la chicete de nostre foy, l'empesche de faire decouler plus abondamment ses biens sur nous;” — “But the smallness and (so to speak) the niggardliness of our faith, hinders him from making his benefits flow more abundantly on us.”;” — “But the smallness and (so to speak) the niggardliness of our faith, hinders him from making his benefits flow more abundantly on us.”