Firstly you cannot raise a sword or knife to it, even to carve its shape. Second you cannot go up to it with steps. It must be with a ramp. The Kli Yakar says these two issurim are because the Mizbei'ach must be the model of Anava, humility.

The sword is symbol of pride. It gives a person a sense of power and dominion over other people. The pasuk in Zos HaBracha says "VaAsher Cherev Ga'avasecha"; the sword is your Ga'ava (your pride). Therefore the mizbei'ach cannot come in contact with a sword even to carve it.

Going up steps is very important. Our whole life is about climbing from Madreiga to Madreiga. However with every new step climbed, there is a well defined sense of accomplishment. Precisely at the time when you have met a challenge and have elevated yourself you are most vulnerable to the Yetzer Hara of pride. Therefore says the Torah when you climb to the Mizbei'ach, elevating yourself each step of the way, go up on a ramp. This way you gradually and quietly continue to rise with each step without attracting attention and passing visible milestones. No one will notice that you are going up and you will soon you will arrive at the top still humble as ever.