A. The Holy Spirit anoints you to witness about Jesus:

ISA 61:1. The Spirit of the Lord GOD is upon me; because the LORD hath anointed me to preach good tidings unto the meek; he hath sent me to bind up the brokenhearted, to proclaim liberty to the captives, and the opening of the prison to them that are bound;

ACT 1:8. But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth.

ACT 4:29. And now, Lord, behold their threatenings: and grant unto thy servants, that with all boldness they may speak thy word,

ACT 4:30. By stretching forth thine hand to heal; and that signs and wonders may be done by the name of thy holy child Jesus.

ACT 4:31. And when they had prayed, the place was shaken where they were assembled together; and they were all filled with the Holy Ghost, and they spake the word of God with boldness.

1TH 1:5. For our gospel came not unto you in word only, but also in power, and in the Holy Ghost, and in much assurance; as ye know what manner of men we were among you for your sake.

COL 1:27. To whom God would make known what is the riches of the glory of this mystery among the Gentiles; which is Christ in you, the hope of glory:

COL 1:28. Whom we preach, warning every man, and teaching every man in all wisdom; that we may present every man perfect in Christ Jesus:

COL 1:29. Whereunto I also labour, striving according to his working, which worketh in me mightily.

B. Only God & His Holy Spirit can really win people:

JOH 6:44. No man can come to me, except the Father which hath sent me draw him: and I will raise him up at the last day.

ZEC 4:6. Then he answered and spake unto me, saying, This is the word of the LORD unto Zerubbabel, saying, Not by might, nor by power, but by my spirit, saith the LORD of hosts.

MAT 10:20. For it is not ye that speak, but the Spirit of your Father which speaketh in you.

JOH 15:5. I am the vine, ye are the branches: He that abideth in me, and I in him, the same bringeth forth much fruit: for without me ye can do nothing.

1COR 3:6. I have planted, Apollos watered; but God gave the increase.