And they said, Believe on the Lord Jesus Christ, and thou shalt be saved… – Acts 16:31

What is the command of the gospel? “Believe on the Lord Jesus Christ, and thou shalt be saved.” Properly speaking, Christ is not an object for seeking, He is not far from any of us; like the brazen serpent uplifted by Moses, He is not so much to be looked for as looked at. We have neither to clamber to heaven to find Him in the loftiness of His Deity and bring Him down; nor dive into the chambers of Hades, to bring Him up again from the dead. Thus saith the Lord, “The word is nigh thee, even in thy mouth, and in thy heart: that is, the word of faith, which we preach; that if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised Him from the dead, thou shalt be saved.” Jesus is Immanuel, God with us. A prayer will reach Him, a wish will find Him, a groan will pierce His heart-do but confide in Him, and He is yours. The first command of the gospel to guilty sinners is not to pray, to search the Scriptures, to attend upon sermons-all these are natural duties, and woe unto the man who neglects any of them; but the command, the special command of the gospel is, “Believe on the Lord Jesus Christ!” ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0947.cfm