For those God foreknew he also predestined to be conformed to the image of his Son, that he might be the firstborn among many brothers and sisters. (NIV)

For those whom He foreknew [of whom He was aware and loved beforehand], He also destined from the beginning [foreordaining them] to be molded into the image of His Son [and share inwardly His likeness], that He might become the firstborn among many brethren. (AMP)

For whom he did foreknow, he also did predestinate to be conformed to the image of his Son, that he might be the firstborn among many brethren. (KJV)