Here "gate" is a metaphor. By referring to himself as "the gate," Jesus is showing that he offers a true way to enter the kingdom of God. AT: "I myself am like that gate." (See: [[rc://en/ta/man/translate/figs-metaphor]])
This is a double negative. In some languages it is more natural to use a positive statement. AT: "comes only to steal" (See: [[rc://en/ta/man/translate/figs-doublenegatives]])
Here the implied metaphor is "sheep," which represents God's people. AT: "steal and kill and destroy the sheep" (See: [[rc://en/ta/man/translate/figs-explicit]] and [[rc://en/ta/man/translate/figs-metaphor]])