Just a few quotes from the good Dr upon the subject of "Alter Calls".
The history of this invitation system is one with which you people ought to be more familiar than anyone else, because it began in America. It began in the 1820s; the real originator of it was Charles G. Finney. It led to a great controversy.
One reason is that there is no evidence that this was done in New Testament times, because then they trusted to the power of the Spirit. Peter preaching on the Day of Pentecost under the power of the Spirit, for instance, had no need to call people forward in decision because, as you remember, the people were so moved and affected by the power of the Word and Spirit that they actually interrupted the preacher, crying out, "Men and brethren, what shall we do?"
The moment you begin to introduce this other element, you are bringing a psychological element. The invitation should be in the message. We believe the Spirit applies the message, so we trust in the power of the Spirit.
I can sum it up by putting it like this: I feel that this pressure which is put upon people to come forward in decision ultimately is due to a lack of faith in the work and operation of the Holy Spirit.
The order in Scripture seems to be this - the truth is presented to the mind, which moves the heart, and that in turn moves the will.