Why was Abraham (peace be upon him) uniquely distinguished by "the close friendship of the Most Merciful" (Khullat al-Rahman), and is this connected to the story of the sacrifice of Ishmael (peace be upon him)?

Abraham, peace be upon him, was not uniquely distinguished by the attribute of being the 'Intimate Friend of the Most Merciful' (Khalīl al-Raḥmān); rather, the Prophet Muhammad, may God bless him and grant him peace, shared in this distinction. This is evidenced by his saying: "Indeed, God has taken me as an intimate friend (khalīl), just as He took Abraham as an intimate friend." Abraham, peace be upon him, earned this great status by realizing monotheism (tawḥīd), disassociating himself from polytheism (shirk (definition)), and fulfilling all of God's commands in the most complete manner.