Is the phrase or concept anywhere in the Bible?
ESV - 6 Therefore, as you received Christ Jesus the Lord, so walk in him.
For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
It his is an interesting question which in a broader view looks at the water in our goldfish bowl, those invisible assumptions we as Christians never question.
I do "accept" this term as a shorthand for acknowledging Jeshu bar Joseph as Messiah, Creator of this universe, God incarnate, The Lord of King David and Lord of me, my daily life past and future.
I "accept" the Holy Spirit into my innermost being. I "accept" my status as child in the Holy Family of God. The term is inadequate, comes from a previous generation where protocol expects modesty. Eg we "accept" an invitation (of marriage, or to dine at the White House).
There are many other inadequate phrases we use that need to be re-written. Things we take from hymns, not actually from the bible such as "Jesus loves me this I know, for the Bible tells me so." No it doesn't! Eg John 3:16 says Father loved us so much He (traded in, gave up) Jesus for us.
To "accept" or simply believe (that Jesus is the Son of Father a God) is in fact a powerful reminder that all the work of removing the sin that separates us from Father's love is done. All we can do is "accept or reject," trust or doubt, bask in the love or hide in fear.