There are some days when we just feel like flopping down and tying ourselves to our bed. Your body becomes tired and weary from working, thinking, and or just being in constant motion all day. When this happens, we choose to stop and let our body do what it is that it wants to do, rest. This same behavior we sometimes apply to obstacles and trials in our life when we attempt to overcome them.
We know when our body is tired, we know when enough is enough, but sometimes you have to know when to push just a little bit more.
Otherwise, you'll always maintain the strength you have. If you don't condition yourself for more, becoming stronger than you are, then you will remain weaker than the individual who does. Just as you say "I've given all I've got, I've given it my best", eventually your best becomes better with continual practice.
In strength training, you use resistance to train your muscles to build strength. You are pushing yourself to become stronger physically. Don't give up or give in so easily to matters of life, build the resistance by going that extra mile. Eventually, you'll realize that your best has become better.
Shared over a cup of tea,
...From My Thoughts To Yours, Jamara