I have never called people forward at the end for this reason; there is a grave danger of people coming forward before they are ready to come forward. We do believe in the work of the Spirit, that He convicts and converts, and He will do His work. There is a danger in bringing people to a "birth," as it were, before they are ready for it.There is a difference between an altar call and an invitation. I believe that every sermon where there are unbelievers in the audience should contain an invitation; an invitation that urges the seeking listener to surrender his life to Christ, and an explanation of the means by which God has made a relationship with Himself possible through him.
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. We are to preach the Word, and if we do it properly, there will be a call to a decision that comes in the message, and then we leave it to the Spirit to act upon people. And of course He does. Some may come immediately at the close of the service to see the minister. I think there should always be an indication that the minister will be glad to see anybody who wants to put questions to him or wants further help. But that is a very different thing from putting pressure upon people to come forward. I feel it is wrong to put pressure directly on the will. 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. - Dr Martyn Lloyd-Jones
But then let that invitation rest on the heart of the hearer. The surrender will take place according to the will of God and the timetable of the Spirit.