If Christ be not risen...

…then is our preaching vain, and your faith is also vain. 1 Corinthians 15:14

No where in the Bible are we told to celebrate His birth but we are told to consistently incorporate into our worship the remembrance of His death.

In fact this is a specific command in God's Word.

We are to do so in order that we never forget that it was Jesus' death that saved our souls from Hell.

It was His death that saved us from our deserved penalty of eternal  damnation due to our sins.

We are to remember His death until He comes again.

If Christ had not died and then rose from the dead then everything we do as professing Christians would indeed be vanity.

It is His death on the cross, the spilling of His blood, which saves us from our sins.

It was His own death and miraculous resurrection that allows our dead spirits to be quickened (born again, brought back to life…).

Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand;
By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain.
For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures;
And that he was buried, and that he rose again the third day according to the scriptures:
And that he was seen of Cephas, then of the twelve:
After that, he was seen of above five hundred brethren at once; of whom the greater part remain unto this present, but some are fallen asleep. 1 Corinthians 15:1-6

For Christ also hath once suffered for sins, the just for the unjust, that he might bring us to God, being put to death in the flesh, but quickened by the Spirit..1 Peter 3:18

It is only through His death that we can be born again.

It was His death that brought us forgiveness of our sins.

It is His death that we are commanded specifically in scriptures to keep in remembrance until He comes again.

The believers before the cross looked forward to the cross.

The believers after the cross look back to the cross.

It was the day that our Saviour Jesus Christ died on the cross that the Psalmist spoke of.

That day was the day that the Lord hath made with the specific purpose of reconciling us back to Him.

That day was the day of Jesus' death and the day where salvation was made available to anyone who would repent, believe and live for our Father through Jesus His Son.

It was that day that we are to rejoice in.

I will praise thee: for thou hast heard me, and art become my salvation. [22] The stone which the builders refused is become the head stone of the corner. [23] This is the Lord's doing; it is marvellous in our eyes. [24] This is the day which the Lord hath made; we will rejoice and be glad in it. Psalm 118:21-24

Don't ever forget His death!

And when he had given thanks, he brake it , and said, Take, eat: this is my body, which is broken for you: this do in remembrance of me. [25] After the same manner also he took the cup, when he had supped, saying, This cup is the new testament in my blood: this do ye, as oft as ye drink it , in remembrance of me. [26] For as often as ye eat this bread, and drink this cup, ye do shew the Lord's death till he come. 1 Corinthians 11:24-26

And he is the propitiation for our sins: and not for ours only, but also for the sins of the whole world. 1 John 2:2

PROPITIATION
1. The act of appeasing wrath and conciliating the favor of an offended person; the act of making propitious.
2. In theology, the atonement or atoning sacrifice offered to God to assuage his wrath and render him propitious to sinners. Christ is the propitiation for the sins of men. Romans 3:25. 1 John 2:2.

For all have sinned, and come short of the glory of God; [24] Being justified freely by his grace through the redemption that is in Christ Jesus: [25] Whom God hath set forth to be a propitiation through faith in his blood, to declare his righteousness for the remission of sins that are past, through the forbearance of God; [26] To declare, I say , at this time his righteousness: that he might be just, and the justifier of him which believeth in Jesus. Romans 3:23-26

It is only through Jesus' death that we can be reconciled back to God.

Jesus was born with the soul purpose of dying for our sins.

Jesus lived with the purpose to give His life as a blood  sacrifice in our place so that we could live forever with our Father in heaven.

But God commendeth his love toward us, in that, while we were yet sinners, Christ died for us. [9] Much more then, being now justified by his blood, we shall be saved from wrath through him. [10] For if, when we were enemies, we were reconciled to God by the death of his Son, much more, being reconciled, we shall be saved by his life. Romans 5:8-10

It's His death and not His birth that saved us.

Let us never forget this crucial point!