"But sanctify the Lord God in your hearts: and be ready always to give an answer to every man that asketh you a reason of the hope that is in you with meekness and fear:" - 1 Peter 3:15 KJV 

What is that hope? 

"Even the mystery which hath been hid from ages and from generations, but now is made manifest to his saints: to whom God would make known what is the riches of the glory of this mystery among the Gentiles; which is Christ in you, the hope of glory:" - Colossians 1:26-27 KJV 

When we receive Christ in us – which is His Spirit in us, the Holy Ghost – we have received the earnest of our inheritance. The Holy Ghost is our foretaste of heavenly glory. 

"In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation: in whom also after that ye believed, ye were sealed with that holy Spirit of promise, which is the earnest of our inheritance until the redemption of the purchased possession, unto the praise of his glory." - Ephesians 1:13-14 KJV 

"To an inheritance incorruptible, and undefiled, and that fadeth not away, reserved in heaven for you," - 1 Peter 1:4 KJV 

"For the hope which is laid up for you in heaven, whereof ye heard before in the word of the truth of the gospel;" - Colossians 1:5 KJV 

God purchased us with His own blood, redeeming us from sin, to be His very own beloved.  

"To the praise of the glory of his grace, wherein he hath made us accepted in the beloved. in whom we have redemption through his blood, the forgiveness of sins, according to the riches of his grace;" - Ephesians 1:6-7 KJV 

"Take heed therefore unto yourselves, and to all the flock, over the which the Holy Ghost hath made you overseers, to feed the church of God, which he hath purchased with his own blood." - Acts 20:28 KJV 

We heard the word of truth, the gospel of our salvation. We repented of our sins, took on His name Jesus in water baptism, and He filled us with His holy Spirit of promise. 

"Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost. For the promise is unto you, and to your children, and to all that are afar off, even as many as the Lord our God shall call." - Acts 2:38-39 KJV 

This is the gospel. Peter preached the gospel on the Day of Pentecost when the church first began. 

"For I am not ashamed of the gospel of Christ: for it is the power of God unto salvation to every one that believeth; to the Jew first, and also to the Greek." - Romans 1:16 KJV 

"In meekness instructing those that oppose themselves; if God peradventure will give them repentance to the acknowledging of the truth; and that they may recover themselves out of the snare of the devil, who are taken captive by him at his will." - 2 Timothy 2:25-26 KJV 

"Let your speech be alway with grace, seasoned with salt, that ye may know how ye ought to answer every man." - Colossians 4:6 KJV 

"Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints; and for me, that utterance may be given unto me, that I may open my mouth boldly, to make known the mystery of the gospel, for which I am an ambassador in bonds: that therein I may speak boldly, as I ought to speak." - Ephesians 6:18-20 KJV