KJV: For the Son of God, Jesus Christ, who was preached among you by us, even by me and Silvanus and Timotheus, was not yea and nay, but in him was yea.
NASB: For the Son of God, Christ Jesus, who was preached among you by us-- by me and Silvanus and Timothy-- was not yes and no, but is yes in Him.
KJV: Paul, and Silvanus, and Timotheus, unto the church of the Thessalonians which is in God the Father and in the Lord Jesus Christ: Grace be unto you, and peace, from God our Father, and the Lord Jesus Christ.
NASB: Paul and Silvanus and Timothy, To the church of the Thessalonians in God the Father and the Lord Jesus Christ: Grace to you and peace.
KJV: By Silvanus, a faithful brother unto you, as I suppose, I have written briefly, exhorting, and testifying that this is the true grace of God wherein ye stand.
NASB: Through Silvanus, our faithful brother (for so I regard him), I have written to you briefly, exhorting and testifying that this is the true grace of God. Stand firm in it!