Did Jesus Christ create the world, or did it happen by itself?

Yes - Jesus Christ created the world. The Bible begins with a deliberate act, not an accident:

In the beginning God created the heaven and the earth.

It presents the universe as the deliberate work of God.

The New Testament identifies the Creator

The New Testament identifies Jesus as the eternal Son through whom everything was created. John calls Him “the Word”:

All things were made by him; and without him was not any thing made that was made.

This same Word became flesh and lived among us as Jesus Christ (John 1:14). His existence did not begin at Bethlehem: He was already with God and was God before creation.

Six ordinary days

Taking Genesis as a literal historical account, God created the world and its living creatures in six ordinary days. He spoke, and what He commanded came into being. The repeated descriptions of evening and morning mark those days.

For in six days the LORD made heaven and earth, the sea, and all that in them is, and rested the seventh day: wherefore the LORD blessed the sabbath day, and hallowed it.

Exodus confirms the six days of creation and God’s rest on the seventh as the pattern for the human working week.

Human beings were deliberately created in God’s image, male and female:

So God created man in his own image, in the image of God created he him; male and female created he them.

Our existence therefore carries dignity and responsibility before our Creator.

He still sustains what He made

Jesus also continues to sustain His creation.

For by him were all things created, that are in heaven, and that are in earth, visible and invisible, whether they be thrones, or dominions, or principalities, or powers: all things were created by him, and for him: And he is before all things, and by him all things consist.

The One who came to save us is also the One who made us.