Jesus is not the father. However Jesus is the same God as the father.
An egg is not a yolk alone, it is not a shell alone, it is not an egg-white alone. All three together are an egg.
You can separate them, and you can call any part of them an egg. But together they are an egg.
Jesus isn't the Father, the Father isn't the Holy Spirit, they are three separate distinct personalities, but together they are God.
Clearly in Matt 7:21 Jesus is talking about the Father. That doesn't make Him any less God.
If Jesus is simply "a" god. How many gods are there in the universe? How many do you worship? Do you worship Jesus? Why or why not?
In Exodus 20:3-4 how many other gods are we told to worship? How about Exodus 34:14; ? Luke 4:8; ?
Our government is made up of 3 branches. Judicial, Executive and Legislative (such as they are). Any one of the three alone is not the government.