Sincerely
3 verses in 2 books of the King James Bible.
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Every Occurrence
Judges 9:16Now therefore, if ye have done truly and sincerely, in that ye have made Abimelech king, and if ye have dealt well with Jerubbaal and his house, and have done unto him according to the deserving of his hands;
Judges 9:19If ye then have dealt truly and sincerely with Jerubbaal and with his house this day, then rejoice ye in Abimelech, and let him also rejoice in you:
Philippians 1:16The one preach Christ of contention, not sincerely, supposing to add affliction to my bonds: