Hashem supports those who are falling – this means that Hashem supports those who are in a downward spiral, falling time and again. Hashem supports everyone, regardless of how far or how often he or she is falling.
Fortunate/praiseworthy are those who can sit in Hashem’s house by directing their minds to Hashem/Torah/chesed/mitzvos wherever they are (except bathrooms and the like). Those who consistently thank Hashem for the goodness in their lives will be fortunate to feel that they are continuously dwelling in the House of Hashem.