What Jesus did, takes care of what we did, who we are, and where we are going.
"10And ye are complete in him, which is the head of all principality and power: 11In whom also ye are circumcised with the circumcision made without hands, in putting off the body of the sins of the flesh by the circumcision of Christ: 12Buried with him in baptism, wherein also ye are risen with him through the faith of the operation of God, who hath raised him from the dead. 13And you, being dead in your sins and the uncircumcision of your flesh, hath he quickened together with him, having forgiven you all trespasses; 14Blotting out the handwriting of ordinances that was against us, which was contrary to us, and took it out of the way, nailing it to his cross; 15And having spoiled principalities and powers, he made a shew of them openly, triumphing over them in it." (Colossians 2: 10-15)
He has made us fulfilled. We have everything that we need in Him (Philippians 4: 19). We no longer identify with our dead flesh, full of sin, but receive His life. We died with Jesus, and even though there is still sin in our members, we reckon ourselves dead to sin (Romans 6: 14) and alive in Christ, who is our life (Colossians 3: 4).
He died for all our sins. All of them:
"Therefore, there is now no condemnation for those who are in Christ Jesus," (Romans 8: 1)
None. At. All.
When Jesus died on the Cross, He took care of all that we were, and made us into Himself:
"9Know ye not that the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abusers of themselves with mankind, 10Nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners, shall inherit the kingdom of God. 11And such were some of you: but ye are washed, but ye are sanctified, but ye are justified in the name of the Lord Jesus, and by the Spirit of our God." (1 Corinthians 6: 8-11)
"What? know ye not that your body is the temple of the Holy Ghost which is in you, which ye have of God, and ye are not your own? 20For ye are bought with a price: therefore glorify God in your body, and in your spirit, which are God's." (1 Corinthians 6: 19-20)
And of course:
"Herein is our love made perfect, that we may have boldness in the day of judgment: because as he is, so are we in this world." (1 John 4: 17)
At the Cross, Jesus took care of everything for us, so that we have no fear where we are going:
"31What shall we then say to these things? If God be for us, who can be against us? 32He that spared not his own Son, but delivered him up for us all, how shall he not with him also freely give us all things?" (Romans 8: 31-32)
"13I can do all things through Christ which strengtheneth me." (Philippians 4: 13)
"19But my God shall supply all your need according to his riches in glory by Christ Jesus." (Philippians 4: 19)
"10For this is the covenant that I will make with the house of Israel after those days, saith the Lord; I will put my laws into their mind, and write them in their hearts: and I will be to them a God, and they shall be to me a people:
11And they shall not teach every man his neighbour, and every man his brother, saying, Know the Lord: for all shall know me, from the least to the greatest.
12For I will be merciful to their unrighteousness, and their sins and their iniquities will I remember no more." (Hebrews 8: 10-12)
"Let your conversation be without covetousness; and be content with such things as ye have: for he hath said, I will never leave thee, nor forsake thee." (Hebrews 13: 5)
No wonder Paul was adamant: Christ and Him Crucified, for in Him we have all things!