1 Kings 20:11
And the king of Israel answered and said, Tell him, Let not him that girdeth on his harness boast himself as he that putteth it off. And the king of Israel answered and said, Tell him, Let not him that girdeth on his harness boast himself as he that putteth it off.
The saying forbids the one who is only strapping on armor for a fight to boast as if the victory were already secured. The beginning of conflict is not the time for triumph, for the outcome is still undecided when the weapons are first taken up. The caution belongs especially to workers in God's cause, who are not to congratulate themselves at the outset of an undertaking. Instead of premature boasting they are to weigh their work thoughtfully, considering it carefully in all its bearings and consequences.