What was John the Baptist commissioned to do for Israel?

John the Baptist was commissioned to Israel to baptize, specifically with a baptism of repentance. That was his mission. This contrast highlights that John's role was baptism, not Paul's gospel preaching, for Paul said Christ sent him not to baptize but to preach the gospel.

Les explains that when John the Baptist was commissioned to Israel, his commission was to baptize, and he baptized with the baptism of repentance; that was his mission. Les then contrasts this with Paul in 1 Corinthians 1:17, where Paul says Christ sent him not to baptize but to preach the gospel. Paul did not come with the wisdom of words, because human eloquence alone cannot get anybody; it is the Holy Spirit who opens the heart, as when the Lord opened Lydia's heart in Philippi so she attended to the things spoken by Paul. This shows the central theme is God's grace and the gospel, not baptism.

John 1:31

And I knew him not: but that he should be made manifest to Israel, therefore am I come baptizing with water.

Mark 1:4

John did baptize in the wilderness, and preach the baptism of repentance for the remission of sins.

What was John the Baptist commissioned to do compared to Paul's commission?

John the Baptist was commissioned to Israel to baptize with the baptism of repentance; that was his mission. By contrast, Paul declares Christ sent him not to baptize but to preach the gospel, not with wisdom of words, because only the Holy Spirit opens the heart.