Exhort and Rebuke

Cry aloud, spare not, lift up thy voice like a trumpet, and shew my people their transgression, and the house of Jacob their sins. (Isaiah 58:1)

51 Ye stiffnecked and uncircumcised in heart and ears, ye do always resist the Holy Ghost: as your fathers did, so do ye. 52 Which of the prophets have not your fathers persecuted? and they have slain them which shewed before of the coming of the Just One; of whom ye have been now the betrayers and murderers: (Acts 7:51-52)

26 Wherefore I take you to record this day, that I am pure from the blood of all men. 27 For I have not shunned to declare unto you all the counsel of God. (Acts 20:26-27)

15 These things speak, and exhort, and rebuke with all authority. Let no man despise thee. (Titus 2:15)

Paul was aware that he had a responsibility to tell Israelite and heathen alike about their sins. Paul did this and in doing so he believed that he had escaped from the blame that would have come to him otherwise.
A friend and I exhorted and rebuked another friend yesterday. It was all appropriate and in private.
I don't think street preaching is the answer.
I don't think walkup evangelism is the answer.
But I do think we can look for friendship with strangers on the street if we are careful about it. We can befriend them, help them and show them that Jesus is the greatest helper.
With God's people we can rebuke them in private or corporately from the pulpit. But although it should be done through proper channels, it must be done. It would be better to shout it "inappropriately" than to never say it at all.
I think this is what Isaiah 58:1 means.