Time is an interesting thing. We all have 24 hours in a day. None of us can live one minute in the past, nor can we put all that much stake into the future. All we have is the right now.
Right now, God is asking for my very best. Oh, I might have given my best yesterday, but that is over and gone. I cannot promise to give my best tomorrow, for I do not know what tomorrow may bring. All I can hope to do is give my best to God in this moment.