Isaiah 50:4 "The Lord GOD hath given me the tongue of the learned, that I should know how to speak a word in season to him that is weary: he wakeneth morning by morning, he wakeneth mine ear to hear as the learned."
To "speak a word in season" is speaking the right word...at the right time...to the right person. When something is said in encouragement at just the right time it can mean the difference to that person. When this is done it is considered speaking "a word in season."
In order to do this we need to be in tune with the Holy Spirit. This is important so we'll know what to say....when to say it and who to say it to. God has something to say through us to someone who is going through a tough time. God will not use a person that is not right with Him and who is not being led of the Holy Spirit.
Someone will no doubt cross your path today that needs to hear that word from you to be encouraged. It could mean the difference of whether they will be saved today....or if they are already saved it could mean the difference in whether they give up on God or not. It is a very serious matter.
Are you to where God can use you to "speak a word in season" to someone today? I hope you are...because God could give you opportunity at any moment.