The Gospel is the good news of Jesus Christ…. But why is Jesus good news?
We must first understand the bad news to fully appreciate the good news.
The bad news is we have all been found guilty and now bear the full wrath of God, who is Holy, Righteous and Just, who will not allow sin to go unpunished and we face an eternal death penalty (Exodus 34:6-7). 

This eternal death penalty will be spent in a place called hell. Jesus described hell as a real place of torment where the worm never dies and the fire is not quenched (Mark 9:48).  Those who have not come to salvation in Christ will spend the rest of eternity paying for the consequences of their sin and forever separated from the life of God (Daniel 12:2; Matthew 25:41-46; 2 Thessalonians 1:7-9).

You may be asking, "Guilty of what?"

Jesus said in Matthew 22:37b-40
" 'You shall love the Lord your God with all your heart, and with all your soul, and with all your mind .' This is the great and foremost commandment. The second is like it, 'You shall love your neighbor as yourself .' On these two commandments depend the whole Law and the Prophets."

We have not loved God, but instead we have despised God and rejected Him (John 3:19-20). We have chosen to worship the creation made by God, instead of God himself (Romans 1:21-23).  

Therefore, God’s perfect judgement over us is:

"... all have sinned and fall short of the glory of God" (Romans 3:23) it is written,
"There is none righteous, not even one;
There is none who understands,
There is none who seeks for God; All have turned aside, together they have become useless;
There is none who does good,
There is not even one."
"Their throat is an open grave, With their tongues they keep deceiving,"
"The poison of asps is under their lips";
"Whose mouth is full of cursing and bitterness";
"Their feet are swift to shed blood , Destruction and misery are in their paths, And the path of peace they have not known ."
"There is no fear of God before their eyes ." (Romans 3:10-18)

Now for the Good News
“But God demonstrates His own love toward us, in that while we were yet sinners, Christ died for us. Much more then, having now been justified by His blood, we shall be saved from the wrath of God through Him.” (Romans 5:8-9)

God showed us his compassion and love by sending His son to die for those who have sinned against Him.

"For God so loved the world, that He gave His only begotten Son, that whoever believes in Him shall not perish, but have eternal life. For God did not send the Son into the world to judge the world, but that the world might be saved through Him. (John 3:16-17)

His lovingkindness provides for us what we cannot do for ourselves, through Christ's perfect righteous life, we are given Christ's perfect righteousness.  

"He made Him who knew no sin to be sin on our behalf, so that we might become the righteousness of God in Him." (2 Corinthians 5:21)

What should our response be to this good news, the Gospel?

"Repent therefore and return, that your sins may be wiped away, in order that times of refreshing may come from the presence of the Lord." - Acts 3:19

To repent is to hate your sin enough that you stop pursuing your sin. Instead you pursue what is right and good out of a love for Jesus Christ, who redeemed us from our sin.

Put your full faith and trust in who Jesus Christ is and what He did in His death and resurrection to fully purchase salvation and your redemption from eternal death.

"Jesus said ..., 'I am the resurrection and the life; he who believes in Me shall live even if he dies.'" - John 11:25
"For by grace you have been saved through faith; and that not of yourselves, it is the gift of God; not as a result of works, that no one should boast." - Ephesians 2:8-9
"But as many as received Him, to them He gave the right to become children of God, even to those who believe in His name." - John 1:12
"... if you confess with your mouth Jesus as Lord, and believe in your heart that God raised Him from the dead, you shall be saved." - Romans 10:9
"... at the name of Jesus every knee should bow, ... and that every tongue should confess that Jesus Christ is Lord, to the glory of God the Father." - Philippians 2:10-11

Pursue holiness and bear fruit in keeping with repentance throughout your life.

 "If we say that we have fellowship with Him and yet walk in the darkness, we lie and do not practice the truth; but if we walk in the Light as He Himself is in the Light, we have fellowship with one another, and the blood of Jesus His Son cleanses us from all sin. If we say that we have no sin, we are deceiving ourselves and the truth is not in us. If we confess our sins, He is faithful and righteous to forgive us our sins and to cleanse us from all unrighteousness." - 1 John 1:6-9

Consider the Gospel
I beg you to take time to consider what has been said here for two reasons:

The first reason is Christ also asked those who followed Him to count the cost. (Luke 14:25-35)
Following after Christ, at this time, is not easy and has no promises of prosperity or good health. It is a life lived in submission to Christ, because of your love for the savior. You will work hard to discipline your body and daily renew your mind, under the power of the Holy Spirit, to the glory of God. (1 Corinthians 9:27, Romans 12:1-2, John 14:16-31, 1 Corinthians 10:31-33)
It is also promised that the world hates the message of Christ and all that He represents. (John 3:19-21)
Those who did not believe Him were willing to kill Him and did. Those who follow Him will be hated like He was. (John 15:18-25)

The second reason is Christ also warned of the imminent Judgement. (Luke 17:22-29)
Your time is short to repent and turn from your sin and seek salvation, through Christ alone. (Acts 17:30-31, John 14:6)
We don't know the day or hour Christ will return or when we will die.  He is coming again to save those who have submitted to His lordship and received salvation through Christ's righteousness. (Hebrews 9:27-28)