This method refers to the Messages app that comes preinstalled on HTC phones. If you use a different app for SMS, this method may not work.
 A menu will appear after a few moments of holding the conversation with your finger.
 This will add the contact to your block list and you will no longer receive SMS messages from that number.
Open Messages.
Tap and hold the message you want to block.
Tap Block Contact.
{"src": "wikihow-all_validation", "title": "How to Block Android Text Messages3"}