There is a real difference between resting because your body genuinely needs it, and skipping a ministry commitment because you are avoiding the effort it costs. I have had to learn to tell those two apart, because they can feel remarkably similar from the inside.
Paul’s honest acknowledgment that our outer self wastes away even while the inner self is renewed (2 Corinthians 4:16) has given me language for showing up tired without pretending the tiredness is not real. Some Sundays I have led a Bible study running on very little sleep, not because I ignored my limits, but because I discerned that this particular tiredness was not the kind that required stepping back. Learning that discernment has taken years, and I still get it wrong sometimes in both directions.