'Resemble' in the Bible

Beloved, we are [even here and] now children of God, and it is not yet made clear what we will be [after His coming]. We know that when He comes and is revealed, we will [as His children] be like Him, because we will see Him just as He is [in all His glory].

We are not to resemble Cain, who was a child of the Evil one and killed his own brother. And why did he kill him? Because his own actions were wicked and his brother's actions righteous.