Mark 1:4

New English Translation

⁴In the wilderness^[a] John the baptizer^[b] began preaching a baptism of repentance for the forgiveness of sins.^[c]

Mark 1:4 tn Or “desert.”
Mark 1:4 tn While Matthew and Luke consistently use the noun βαπτίστης (baptistēs, “[the] Baptist”) to refer to John, as a kind of a title, Mark prefers the substantival participle ὁ βαπτίζων (ho baptizōn, “the one who baptizes, the baptizer”) to describe him (only twice does he use the noun [Mark 6:25; 8:28]).
Mark 1:4 sn A baptism of repentance for the forgiveness of sins was a call for preparation for the arrival of the Lord’s salvation. To participate in this baptism was a recognition of the need for God’s forgiveness with a sense that one needed to live differently as a response to it.

Mark 1:7

New English Translation

⁷He proclaimed,^[a] “One more powerful than I am is coming after me; I am not worthy^[b] to bend down and untie the strap^[c] of his sandals.

Mark 1:7 tn Grk “proclaimed, saying.” The participle λέγων (legōn) is redundant in contemporary English and has not been translated.
Mark 1:7 tn Grk “of whom I am not worthy.”sn The humility of John is evident in the statement I am not worthy. This was considered one of the least worthy tasks of a slave, and John did not consider himself worthy to do even that for the one to come, despite the fact he himself was a prophet.
Mark 1:7 tn The term refers to the leather strap or thong used to bind a sandal. This is often viewed as a collective singular and translated as a plural, “the straps of his sandals,” but it may be more emphatic to retain the singular here.

⁸I baptize you with water, but he will baptize you with the Holy Spirit.”

New English Translation (NET)