“The time is fulfilled, and the kingdom of God is at hand. Repent, and believe in the gospel.” – Mark 1:15

Faith and repentance go together. They must. If I trust Christ to save me from sin, I am at the same time repenting of sin, and my mind is changed in relation to sin, and everything else that has to do with its state. All the fruits meet for repentance are contained in faith itself. You will never find that a man who trusts Christ remains an enemy of God, or a lover of sin. The fact that he accepts the atonement provided is proof positive that he loathes sin, and that his mind is thoroughly changed in reference to God. Moreover, as to all the graces which are produced in the Christian afterwards, are they not all to be found in the embryo in faith? “Only believe, and you shall be saved,” is the cry which many sneer at, and others misunderstand; but do you know what “only believe” means? Do you know what a world of meaning lies in that word? Read that famous chapter to the Hebrews, and see what faith has done and is still able to do, and you will see that it is no trifle…Faith is in itself one of the noblest of graces; it is the compendium of all virtues; and as sometimes there will lie within one single ear enough seed to make a whole garden fertile, so, within that one word “faith,” there lies enough of virtue to make earth blessed; enough of grace, if the Spirit make it to grow, to turn the fallen into the perfect. Faith is not the easy and light thing men think. Far are we from ascribing salvation to the profession of a mere creed, we loathe the idea; neither do we ascribe salvation to a fond persuasion, but we do ascribe salvation to Jesus Christ, and the obtaining of it to that simple, child-like confidence which lovingly casts itself into the arms of Him who gave both His hands to the nail and suffered to the death for the sins of His people. He who believes, then, is saved, rest assured of that. “Whosoever believeth that Jesus is the Christ is born of God.”~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0979.cfm